diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/ChTextTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/ChTextTest.java
index 5aca7cfd69a..3b28a4aad14 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/ChTextTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/ChTextTest.java
@@ -14,7 +14,7 @@
 import org.hamcrest.MatcherAssert;
 import org.hamcrest.Matchers;
 import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -31,15 +31,14 @@ final class ChTextTest {
     /**
      * Test file path in temp dir.
      */
-    private static Path file;
+    private Path file;
 
-    @BeforeAll
-    @ExtendWith(MktmpResolver.class)
-    static void setUp(@Mktmp final Path dir) throws IOException {
-        ChTextTest.file = dir.resolve("tags.txt");
+    @BeforeEach
+    void setUp(@Mktmp final Path dir) throws IOException {
+        this.file = dir.resolve("tags.txt");
         new Saved(
             new ResourceOf("org/eolang/maven/commits/tags.txt"),
-            ChTextTest.file
+            this.file
         ).value();
     }
 
@@ -72,7 +71,7 @@ void readsCorrectHashByTagFromFile(
     ) {
         MatcherAssert.assertThat(
             "ChText should read the correct hash by tag from the file, but it didn't",
-            new ChText(ChTextTest.file, tag).value(),
+            new ChText(this.file, tag).value(),
             Matchers.equalTo(hash)
         );
     }
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/FpDefaultTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/FpDefaultTest.java
index 81a9cd1bf9d..f55feac3ff4 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/FpDefaultTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/FpDefaultTest.java
@@ -25,32 +25,13 @@
 @SuppressWarnings("PMD.TooManyMethods")
 @ExtendWith(MktmpResolver.class)
 final class FpDefaultTest {
-    /**
-     * Lambda content.
-     */
-    private static final String LAMBDA_CONTENT = "Footprint content";
-
-    /**
-     * Target content.
-     */
-    private static final String TARGET_CONTENT = "Target content";
-
-    /**
-     * Cache content.
-     */
-    private static final String CACHE_CONTENT = "Cache content";
-
-    /**
-     * Snapshot.
-     */
-    private static final String SNAPSHOT = "SNAPSHOT";
 
     @Test
     void failsIfSourcePathNotExists() {
         Assertions.assertThrows(
             IllegalStateException.class,
             () -> new FpDefault(
-                src -> FpDefaultTest.LAMBDA_CONTENT,
+                src -> this.footprintContent(),
                 Paths.get("/file-doesnt-exist"),
                 "",
                 "",
@@ -66,7 +47,7 @@ void doesNothingWhenTargetIsOlderThanSource(@Mktmp final Path temp) throws Excep
         final Path target = FpDefaultTest.existedTarget(temp);
         FpDefaultTest.makeOlder(target);
         final Path result = new FpDefault(
-            src -> FpDefaultTest.LAMBDA_CONTENT,
+            src -> this.footprintContent(),
             temp,
             "1.2.3",
             "abcdef",
@@ -80,7 +61,7 @@ void doesNothingWhenTargetIsOlderThanSource(@Mktmp final Path temp) throws Excep
         MatcherAssert.assertThat(
             "The content of target file has not to be changed",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.TARGET_CONTENT)
+            Matchers.equalTo("Target content")
         );
     }
 
@@ -92,20 +73,20 @@ void updatesOnlyTargetFromSourceIfNoTargetAndCacheIsNotCacheable(
         final Path target = FpDefaultTest.notExistedTarget(temp);
         assert Files.notExists(target);
         new FpDefault(
-            src -> FpDefaultTest.LAMBDA_CONTENT,
+            src -> this.footprintContent(),
             temp,
-            FpDefaultTest.SNAPSHOT,
+            "SNAPSHOT",
             "",
             Paths.get("cache1.txt")
         ).apply(source, target);
         MatcherAssert.assertThat(
             "Target file must be updated from content function, but it didn't",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
         MatcherAssert.assertThat(
             "Cache file has not to be updated",
-            temp.resolve(FpDefaultTest.SNAPSHOT).resolve("cache.txt").toFile().exists(),
+            temp.resolve("SNAPSHOT").resolve("cache.txt").toFile().exists(),
             Matchers.equalTo(false)
         );
     }
@@ -118,20 +99,20 @@ void updatesOnlyTargetFromSourceIfYoungerTargetAndCacheIsNotCacheable(
         final Path target = FpDefaultTest.existedTarget(temp);
         FpDefaultTest.makeOlder(source);
         new FpDefault(
-            src -> FpDefaultTest.LAMBDA_CONTENT,
+            src -> this.footprintContent(),
             temp,
-            FpDefaultTest.SNAPSHOT,
+            "SNAPSHOT",
             "",
             Paths.get("cache2.txt")
         ).apply(source, target);
         MatcherAssert.assertThat(
             "Target file must be updated from content function, but it didn't",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
         MatcherAssert.assertThat(
             "Cache file has not to be updated",
-            temp.resolve(FpDefaultTest.SNAPSHOT).resolve("cache.txt").toFile().exists(),
+            temp.resolve("SNAPSHOT").resolve("cache.txt").toFile().exists(),
             Matchers.equalTo(false)
         );
     }
@@ -149,12 +130,12 @@ void updatesBothIfTargetYoungerAndNotExistedCacheableCache(
         MatcherAssert.assertThat(
             "Target content must be updated from lambda, but it didn't",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
         MatcherAssert.assertThat(
             "Cache content must be updated from lambda, but it didn't",
             new TextOf(cache.path()).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
     }
 
@@ -168,12 +149,12 @@ void updatesBothNoTargetAndNotExistedCacheableCache(@Mktmp final Path temp) thro
         MatcherAssert.assertThat(
             "Target content must be updated from lambda, but it didn't",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
         MatcherAssert.assertThat(
             "Cache content must be updated from lambda, but it didn't",
             new TextOf(cache.path()).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
     }
 
@@ -190,12 +171,12 @@ void updatesBothIfTargetYoungerAndExistedCacheableCacheIsYounger(
         MatcherAssert.assertThat(
             "Target content must be updated from lambda, but it didn't",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
         MatcherAssert.assertThat(
             "Cache content must be updated from lambda, but it didn't",
             new TextOf(cache.path()).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
     }
 
@@ -212,12 +193,12 @@ void updatesBothIfNoTargetAndExistedCacheableCacheIsYounger(
         MatcherAssert.assertThat(
             "Target content must be updated from lambda, but it didn't",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
         MatcherAssert.assertThat(
             "Cache content must be updated from lambda, but it didn't",
             new TextOf(cache.path()).asString(),
-            Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT)
+            Matchers.equalTo(this.footprintContent())
         );
     }
 
@@ -234,12 +215,12 @@ void copiesFromCacheIfTargetYoungerAndExistedCacheableCacheOlder(
         MatcherAssert.assertThat(
             "Target content must be updated from cache, but it didn't",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.CACHE_CONTENT)
+            Matchers.equalTo(this.cacheContent())
         );
         MatcherAssert.assertThat(
             "Cache content must not be changed, but it did",
             new TextOf(cache.path()).asString(),
-            Matchers.equalTo(FpDefaultTest.CACHE_CONTENT)
+            Matchers.equalTo(this.cacheContent())
         );
     }
 
@@ -257,12 +238,12 @@ void copiesFromCacheIfNoTaretAndExistedCacheableCacheOlder(
         MatcherAssert.assertThat(
             "Target content must be updated from cache, but it didn't",
             new TextOf(target).asString(),
-            Matchers.equalTo(FpDefaultTest.CACHE_CONTENT)
+            Matchers.equalTo(this.cacheContent())
         );
         MatcherAssert.assertThat(
             "Cache content must not be changed, but it did",
             new TextOf(cache.path()).asString(),
-            Matchers.equalTo(FpDefaultTest.CACHE_CONTENT)
+            Matchers.equalTo(this.cacheContent())
         );
     }
 
@@ -275,7 +256,7 @@ void skipsCacheIfItIsNotEnabled(@Mktmp final Path temp) throws Exception {
         FpDefaultTest.makeOlder(source);
         FpDefaultTest.makeOlder(cache.path(), 100_000);
         new FpDefault(
-            src -> FpDefaultTest.LAMBDA_CONTENT,
+            src -> this.footprintContent(),
             cache.base,
             cache.semver,
             () -> cache.hash,
@@ -286,8 +267,8 @@ void skipsCacheIfItIsNotEnabled(@Mktmp final Path temp) throws Exception {
             "Global cache must be skipped because of the boolean flag",
             new TextOf(target).asString(),
             Matchers.allOf(
-                Matchers.equalTo(FpDefaultTest.LAMBDA_CONTENT),
-                Matchers.not(Matchers.equalTo(FpDefaultTest.CACHE_CONTENT))
+                Matchers.equalTo(this.footprintContent()),
+                Matchers.not(Matchers.equalTo(this.cacheContent()))
             )
         );
     }
@@ -300,7 +281,7 @@ void throwsNpeIfHashIsNull(@Mktmp final Path temp) throws IOException {
         Assertions.assertThrows(
             NullPointerException.class,
             () -> new FpDefault(
-                src1 -> FpDefaultTest.LAMBDA_CONTENT,
+                src1 -> this.footprintContent(),
                 cache.base,
                 cache.semver,
                 null,
@@ -310,6 +291,20 @@ void throwsNpeIfHashIsNull(@Mktmp final Path temp) throws IOException {
         );
     }
 
+    /**
+     * Returns the cache content.
+     */
+    private String cacheContent() {
+        return "Cache content";
+    }
+
+    /**
+     * Returns the footprint content.
+     */
+    private String footprintContent() {
+        return "Footprint content";
+    }
+
     /**
      * Apply default footprint.
      * @param cache Cache
@@ -320,8 +315,9 @@ void throwsNpeIfHashIsNull(@Mktmp final Path temp) throws IOException {
     private static void defaultFootprint(
         final Cache cache, final Path source, final Path target
     ) throws Exception {
+        final String footprint = "Footprint content";
         new FpDefault(
-            src -> FpDefaultTest.LAMBDA_CONTENT,
+            src -> footprint,
             cache.base,
             cache.semver,
             cache.hash,
@@ -368,7 +364,7 @@ private static Path notExistedSource(final Path temp) {
      */
     private static Path existedTarget(final Path temp) throws IOException {
         final Path source = FpDefaultTest.notExistedTarget(temp);
-        return FpDefaultTest.existedFile(source, FpDefaultTest.TARGET_CONTENT);
+        return FpDefaultTest.existedFile(source, "Target content");
     }
 
     /**
@@ -410,7 +406,7 @@ private static void makeOlder(final Path file, final long time) throws IOExcepti
      */
     private static Cache existedCache(final Path temp) throws IOException {
         final Cache cache = FpDefaultTest.notExistedCache(temp);
-        FpDefaultTest.existedFile(cache.path(), FpDefaultTest.CACHE_CONTENT);
+        FpDefaultTest.existedFile(cache.path(), "Cache content");
         return cache;
     }
 
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/MjPlaceTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/MjPlaceTest.java
index d76a5ff5345..6d041d4178d 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/MjPlaceTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/MjPlaceTest.java
@@ -26,16 +26,6 @@
 @ExtendWith(MktmpResolver.class)
 final class MjPlaceTest {
 
-    /**
-     * The default folder for placed binaries.
-     */
-    private static final String TARGET_CLASSES = "target/classes";
-
-    /**
-     * Test library for all binaries.
-     */
-    private static final String LIBRARY = "foo/hello/-/0.1";
-
     @Test
     void placesBinaries(@Mktmp final Path temp) throws Exception {
         MjPlaceTest.saveBinary(temp, "EObar/x.bin");
@@ -67,13 +57,13 @@ void skipsAlreadyPlacedBinaries(@Mktmp final Path temp) throws IOException {
             "PlaceMojo must skip already placed binaries, but it doesn't",
             new FakeMaven(temp)
                 .withPlacedBinary(
-                    temp.resolve(MjPlaceTest.TARGET_CLASSES).resolve(binary)
+                    temp.resolve(this.targetClasses()).resolve(binary)
                 )
-                .execute(MjPlace.class)
-                .result()
-                .get("target/classes/org/eolang/f/x.a.class")
-                .toFile()
-                .lastModified(),
+            .execute(MjPlace.class)
+            .result()
+            .get("target/classes/org/eolang/f/x.a.class")
+            .toFile()
+            .lastModified(),
             Matchers.equalTo(before)
         );
     }
@@ -105,12 +95,12 @@ void placesWithoutBinaries(@Mktmp final Path temp) throws IOException {
         MatcherAssert.assertThat(
             String.format(
                 "PlaceMojo must not place binaries from %s",
-                MjPlaceTest.TARGET_CLASSES
+                this.targetClasses()
             ),
             new FakeMaven(temp)
                 .execute(MjPlace.class)
                 .result(),
-            Matchers.not(Matchers.hasKey(MjPlaceTest.TARGET_CLASSES))
+            Matchers.not(Matchers.hasKey(this.targetClasses()))
         );
     }
 
@@ -123,7 +113,7 @@ void placesDefaultJnaBinaries(@Mktmp final Path temp) throws Exception {
                 .with("ignoreRuntime", true)
                 .execute(new FakeMaven.Place())
                 .result()
-                .get(MjPlaceTest.TARGET_CLASSES),
+                .get(this.targetClasses()),
             new ContainsFiles("**/jna-*.class")
         );
     }
@@ -137,12 +127,12 @@ void placesWithoutResolveDirectory(@Mktmp final Path temp) throws IOException {
                     "PlaceMojo must not place binaries from %s",
                     "if the resolve directory does not exist"
                 ),
-                MjPlaceTest.TARGET_CLASSES
+                this.targetClasses()
             ),
             new FakeMaven(temp)
                 .execute(MjPlace.class)
                 .result(),
-            Matchers.not(Matchers.hasKey(MjPlaceTest.TARGET_CLASSES))
+            Matchers.not(Matchers.hasKey(this.targetClasses()))
         );
     }
 
@@ -182,7 +172,7 @@ void placesAllEoRuntimeClasses(@Mktmp final Path temp) throws IOException {
                 .with("resolveJna", false)
                 .execute(new FakeMaven.Place())
                 .result()
-                .get(MjPlaceTest.TARGET_CLASSES),
+                .get(this.targetClasses()),
             new ContainsFiles("**/eo-runtime-*.class")
         );
         MatcherAssert.assertThat(
@@ -202,7 +192,7 @@ void placesWithoutEoRuntimeClasses(@Mktmp final Path temp) throws IOException {
                 .with("resolveJna", false)
                 .execute(new FakeMaven.Place())
                 .result()
-                .get(MjPlaceTest.TARGET_CLASSES),
+                .get(this.targetClasses()),
             Matchers.not(new ContainsFiles("**/eo-runtime-*.class"))
         );
     }
@@ -240,11 +230,18 @@ void placesAgainIfWasUnplaced(@Mktmp final Path temp) throws Exception {
         );
     }
 
+    /**
+     * Returns the target classes.
+     */
+    private String targetClasses() {
+        return "target/classes";
+    }
+
     /**
      * Save binary to {@link MjResolve#DIR} folder.
      * The method emulates the situation when we have some resolved binaries.
      *
-     * @param temp Temp test directory.
+     * @param temp   Temp test directory.
      * @param binary Binary name.
      * @throws IOException In case of error.
      */
@@ -256,9 +253,9 @@ private static void saveBinary(final Path temp, final String binary) throws IOEx
      * Save binary to {@link MjResolve#DIR} folder.
      * The method emulates the situation when we have some resolved binaries.
      *
-     * @param temp Temp test directory.
+     * @param temp    Temp test directory.
      * @param content Content of the binary.
-     * @param binary Binary name.
+     * @param binary  Binary name.
      * @throws IOException In case of error.
      */
     private static void saveBinary(
@@ -269,7 +266,7 @@ private static void saveBinary(
         new Saved(
             content,
             temp.resolve("target").resolve(MjResolve.DIR).resolve(
-                Paths.get(String.format("%s/%s", MjPlaceTest.LIBRARY, binary))
+                Paths.get(String.format("%s/%s", "foo/hello/-/0.1", binary))
             )
         ).value();
     }
@@ -278,7 +275,7 @@ private static void saveBinary(
      * Save binary to classes folder.
      * The method emulates the situation when we already have some placed binaries.
      *
-     * @param temp Temp test directory.
+     * @param temp   Temp test directory.
      * @param binary Binary name.
      * @throws IOException In case of error.
      */
@@ -293,9 +290,9 @@ private static void saveAlreadyPlacedBinary(
      * Save binary to classes folder.
      * The method emulates the situation when we already have some placed binaries.
      *
-     * @param temp Temp test directory.
+     * @param temp    Temp test directory.
      * @param content Content of the binary.
-     * @param binary Binary name.
+     * @param binary  Binary name.
      * @throws IOException In case of error.
      */
     private static void saveAlreadyPlacedBinary(
@@ -303,19 +300,21 @@ private static void saveAlreadyPlacedBinary(
         final String content,
         final String binary
     ) throws IOException {
+        final String targets = "target/classes";
         new Saved(
             content,
-            temp.resolve(MjPlaceTest.TARGET_CLASSES).resolve(binary)
+            temp.resolve(targets).resolve(binary)
         ).value();
     }
 
     /**
      * Path to the placed binary.
-     * @param temp Temp test directory
+     *
+     * @param temp   Temp test directory
      * @param binary Binary name.
      * @return Path to the placed binary.
      */
     private static Path pathToPlacedBinary(final Path temp, final String binary) {
-        return temp.resolve(MjPlaceTest.TARGET_CLASSES).resolve(binary);
+        return temp.resolve("target/classes").resolve(binary);
     }
 }
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/MjPullTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/MjPullTest.java
index 7a94ef5dfc1..6ada1f15e27 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/MjPullTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/MjPullTest.java
@@ -33,21 +33,17 @@
 @ExtendWith(WeAreOnline.class)
 @ExtendWith(MktmpResolver.class)
 final class MjPullTest {
-    /**
-     * Stdout.
-     */
-    private static final String STDOUT = "org.eolang.io.stdout";
 
     @Test
     void pullsSuccessfully(@Mktmp final Path temp) throws IOException {
         final FakeMaven maven = new FakeMaven(temp);
         maven.foreignTojos()
-            .add(MjPullTest.STDOUT)
+            .add(this.stdout())
             .withVersion("*.*.*");
         maven.with("skip", false).execute(MjPull.class);
         MatcherAssert.assertThat(
             "PullMojo should have pulled stdout object, but didn't",
-            MjPullTest.exists(temp, MjPullTest.STDOUT),
+            MjPullTest.exists(temp, this.stdout()),
             Matchers.is(true)
         );
     }
@@ -66,7 +62,7 @@ void pullsFromProbes(@Mktmp final Path temp) throws IOException {
             .execute(new FakeMaven.Pull());
         MatcherAssert.assertThat(
             "PullMojo should have pulled from probes, but it didn't",
-            MjPullTest.exists(temp, MjPullTest.STDOUT),
+            MjPullTest.exists(temp, this.stdout()),
             Matchers.is(true)
         );
     }
@@ -79,7 +75,7 @@ void pullsUsingOfflineHashFile(@Mktmp final Path temp) throws IOException {
         ).value();
         final FakeMaven maven = new FakeMaven(temp);
         maven.foreignTojos()
-            .add(MjPullTest.STDOUT)
+            .add(this.stdout())
             .withVersion("*.*.*");
         maven.with("skip", false)
             .with(
@@ -98,7 +94,7 @@ void pullsUsingOfflineHashFile(@Mktmp final Path temp) throws IOException {
     void pullsUsingOfflineHash(@Mktmp final Path temp) throws IOException {
         final FakeMaven maven = new FakeMaven(temp);
         maven.foreignTojos()
-            .add(MjPullTest.STDOUT)
+            .add(this.stdout())
             .withVersion("*.*.*");
         maven.with("skip", false)
             .with(
@@ -117,14 +113,14 @@ void pullsUsingOfflineHash(@Mktmp final Path temp) throws IOException {
     void skipsPullMojo(@Mktmp final Path temp) throws IOException {
         final FakeMaven maven = new FakeMaven(temp);
         maven.foreignTojos()
-            .add(MjPullTest.STDOUT)
+            .add(this.stdout())
             .withScope("compile")
             .withVersion("*.*.*");
         maven.with("skip", true)
             .execute(MjPull.class);
         MatcherAssert.assertThat(
             "PullMojo must skip pulling, but it doesn't",
-            MjPullTest.exists(temp, MjPullTest.STDOUT),
+            MjPullTest.exists(temp, this.stdout()),
             Matchers.is(false)
         );
     }
@@ -242,6 +238,13 @@ void getsAlreadyPulledResultsFromCache(@Mktmp final Path temp) throws Exception
         );
     }
 
+    /**
+     * Returns the stdout path.
+     */
+    private String stdout() {
+        return "org.eolang.io.stdout";
+    }
+
     /**
      * Check if the given source file exists in the target directory.
      *
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/MjRegisterTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/MjRegisterTest.java
index 4081e1facb2..f447d5b529d 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/MjRegisterTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/MjRegisterTest.java
@@ -22,15 +22,6 @@
  */
 @ExtendWith(MktmpResolver.class)
 final class MjRegisterTest {
-    /**
-     * Parameter for source directory.
-     */
-    private static final String PARAM = "sourcesDir";
-
-    /**
-     * Source directory.
-     */
-    private static final String SOURCES = "src/eo";
 
     @Test
     void registersOkNames(@Mktmp final Path temp) throws IOException {
@@ -39,7 +30,7 @@ void registersOkNames(@Mktmp final Path temp) throws IOException {
             temp.resolve("src/eo/org/eolang/maven/abc-def.eo")
         ).value();
         final FakeMaven maven = new FakeMaven(temp)
-            .with(MjRegisterTest.PARAM, temp.resolve(MjRegisterTest.SOURCES).toFile())
+            .with("sourcesDir", temp.resolve("src/eo").toFile())
             .execute(new FakeMaven.Register());
         MatcherAssert.assertThat(
             "The resource must exist, but it doesn't",
@@ -55,7 +46,7 @@ void doesNotFailWhenNoStrictNames(@Mktmp final Path temp) throws IOException {
             temp.resolve("src/eo/org/eolang/maven/.abc.eo")
         ).value();
         final FakeMaven maven = new FakeMaven(temp)
-            .with(MjRegisterTest.PARAM, temp.resolve(MjRegisterTest.SOURCES).toFile())
+            .with("sourcesDir", temp.resolve("src/eo").toFile())
             .with("strictFileNames", false)
             .execute(new FakeMaven.Register());
         MatcherAssert.assertThat(
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/MjResolveTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/MjResolveTest.java
index f7870288862..2ea228727bc 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/MjResolveTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/MjResolveTest.java
@@ -28,16 +28,6 @@
 @SuppressWarnings({"PMD.AvoidDuplicateLiterals", "PMD.TooManyMethods"})
 final class MjResolveTest {
 
-    /**
-     * The message that the .class file must exist.
-     */
-    private static final String CLASS_MUST_EXIST = "The class file must exist, but it doesn't";
-
-    /**
-     * The message that the .class file must not exist.
-     */
-    private static final String CLASS_NOT_EXIST = "The class file must not exist, but it doesn't";
-
     @Test
     void resolvesWithSingleDependency(@Mktmp final Path temp) throws IOException {
         new FakeMaven(temp)
@@ -58,7 +48,7 @@ void resolvesWithSingleDependency(@Mktmp final Path temp) throws IOException {
             FileMatchers.anExistingDirectory()
         );
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_MUST_EXIST,
+            "The class file must exist, but it doesn't",
             path.resolve("eo-runtime-0.7.0.class").toFile(),
             FileMatchers.anExistingFile()
         );
@@ -99,7 +89,7 @@ void resolvesWithoutAnyDependencies(@Mktmp final Path temp) throws IOException {
             FileMatchers.anExistingDirectory()
         );
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_MUST_EXIST,
+            "The class file must exist, but it doesn't",
             path,
             new ContainsFiles("**/eo-runtime-*.class")
         );
@@ -110,7 +100,7 @@ void resolvesWithEoRuntimeDependency(@Mktmp final Path temp) throws IOException
         final FakeMaven maven = new FakeMaven(temp);
         maven.withHelloWorld().execute(new FakeMaven.Resolve());
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_MUST_EXIST,
+            "The class file must exist, but it doesn't",
             maven.targetPath(),
             new ContainsFiles("**/eo-runtime-*.class")
         );
@@ -123,7 +113,7 @@ void resolvesWithoutEoRuntimeDependency(@Mktmp final Path temp) throws IOExcepti
             .with("ignoreRuntime", true)
             .execute(new FakeMaven.Resolve());
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_NOT_EXIST,
+            "The class file must not exist, but it doesn't",
             maven.targetPath(),
             Matchers.not(new ContainsFiles("**/eo-runtime-*.class"))
         );
@@ -140,7 +130,7 @@ void resolvesIfRuntimeDependencyComesFromTojos(@Mktmp final Path temp) throws IO
             "[] > main"
         ).execute(new FakeMaven.Resolve());
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_MUST_EXIST,
+            "The class file must exist, but it doesn't",
             maven.targetPath(),
             new ContainsFiles("**/eo-runtime-0.22.1.class")
         );
@@ -157,7 +147,7 @@ void resolvesIfRuntimeDependencyComesFromTojosButParamIsFalse(@Mktmp final Path
             "[] > main"
         ).with("ignoreRuntime", true).execute(new FakeMaven.Resolve());
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_NOT_EXIST,
+            "The class file must not exist, but it doesn't",
             maven.targetPath(),
             Matchers.not(new ContainsFiles("**/eo-runtime-*.class"))
         );
@@ -176,7 +166,7 @@ void resolvesWithRuntimeDependencyFromPom(@Mktmp final Path temp) throws IOExcep
             .with("project", project)
             .execute(new FakeMaven.Resolve());
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_MUST_EXIST,
+            "The class file must exist, but it doesn't",
             maven.targetPath(),
             new ContainsFiles("**/eo-runtime-0.7.0.class")
         );
@@ -193,7 +183,7 @@ void resolvesWithoutTransitiveDependencies(@Mktmp final Path temp) throws IOExce
             )
             .execute(new FakeMaven.Resolve());
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_MUST_EXIST,
+            "The class file must exist, but it doesn't",
             maven.targetPath(),
             new ContainsFiles("**/eo-runtime-*.class")
         );
@@ -277,7 +267,7 @@ void resolvesWithConflictingDependenciesNoFail(@Mktmp final Path temp) throws IO
         maven.with("ignoreVersionConflicts", true)
             .execute(new FakeMaven.Resolve());
         MatcherAssert.assertThat(
-            MjResolveTest.CLASS_MUST_EXIST,
+            "The class file must exist, but it doesn't",
             maven.targetPath(),
             new ContainsFiles("**/eo-runtime-*.class")
         );
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/OyIndexedTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/OyIndexedTest.java
index 1ee7235953f..71d0079b3de 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/OyIndexedTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/OyIndexedTest.java
@@ -20,11 +20,6 @@
  */
 final class OyIndexedTest {
 
-    /**
-     * Object name for stdout.
-     */
-    private static final String STDOUT_OBJECT = "org.eolang.io.stdout";
-
     @Test
     void getsFromDelegate() throws Exception {
         MatcherAssert.assertThat(
@@ -41,7 +36,7 @@ void getsFromDelegate() throws Exception {
     void containsInRealIndex() throws IOException {
         MatcherAssert.assertThat(
             "OyIndexed must contain stdout object, but it doesn't",
-            new OyIndexed(new Objectionary.Fake()).contains(OyIndexedTest.STDOUT_OBJECT),
+            new OyIndexed(new Objectionary.Fake()).contains(this.stdout()),
             Matchers.is(true)
         );
     }
@@ -52,8 +47,8 @@ void containsInFakeIndex() throws IOException {
             "OyIndexed with fake index must contain stdout object, but it doesn't",
             new OyIndexed(
                 new Objectionary.Fake(),
-                new ObjectsIndex(() -> Collections.singleton(OyIndexedTest.STDOUT_OBJECT))
-            ).contains(OyIndexedTest.STDOUT_OBJECT),
+                new ObjectsIndex(() -> Collections.singleton(this.stdout()))
+            ).contains(this.stdout()),
             Matchers.is(true)
         );
     }
@@ -69,7 +64,7 @@ void checksContainsInDelegateIfExceptionHappensInIndex() throws IOException {
                         throw new IllegalStateException("Fake exception");
                     }
                 )
-            ).contains(OyIndexedTest.STDOUT_OBJECT),
+            ).contains(this.stdout()),
             Matchers.is(true)
         );
     }
@@ -79,7 +74,7 @@ void checksContainsInDelegateIfExceptionHappensInIndex() throws IOException {
     void checksIsDirectoryForObject() throws IOException {
         MatcherAssert.assertThat(
             "OyIndexed must contain stdout object, but it doesn't",
-            new OyIndexed(new Objectionary.Fake()).isDirectory(OyIndexedTest.STDOUT_OBJECT),
+            new OyIndexed(new Objectionary.Fake()).isDirectory(this.stdout()),
             Matchers.is(false)
         );
     }
@@ -93,4 +88,11 @@ void checksIsDirectoryForDirectory() throws IOException {
             Matchers.is(false)
         );
     }
+
+    /**
+     * Returns the stdout path.
+     */
+    private String stdout() {
+        return "org.eolang.io.stdout";
+    }
 }
diff --git a/eo-runtime/src/test/java/EOorg/EOeolang/EOnk/EOsocketTest.java b/eo-runtime/src/test/java/EOorg/EOeolang/EOnk/EOsocketTest.java
index 9b86619647b..be04edf7438 100644
--- a/eo-runtime/src/test/java/EOorg/EOeolang/EOnk/EOsocketTest.java
+++ b/eo-runtime/src/test/java/EOorg/EOeolang/EOnk/EOsocketTest.java
@@ -54,22 +54,13 @@
     "JTCOP.RuleAllTestsHaveProductionClass"
 })
 final class EOsocketTest {
-    /**
-     * Localhost IP.
-     */
-    private static final String LOCALHOST = "127.0.0.1";
-
-    /**
-     * Random.
-     */
-    private static final Random RANDOM = new Random();
 
     @Test
     void connectsToLocalServerViaSocketObject() throws IOException {
         final RandomServer server = new RandomServer().started();
         try {
             final Phi socket = Phi.Φ.take("org.eolang.nk.socket").copy();
-            socket.put(0, new Data.ToPhi(EOsocketTest.LOCALHOST));
+            socket.put(0, new Data.ToPhi(this.localhost()));
             socket.put(1, new Data.ToPhi(server.port));
             final Phi connected = socket.take("connect").copy();
             connected.put(0, new Simple());
@@ -98,7 +89,7 @@ void sendsAndReceivesMessageViaSocketObject() throws InterruptedException, IOExc
         final Thread server = new Thread(
             () -> {
                 final Phi socket = Phi.Φ.take("org.eolang.nk.socket").copy();
-                socket.put(0, new Data.ToPhi(EOsocketTest.LOCALHOST));
+                socket.put(0, new Data.ToPhi(this.localhost()));
                 socket.put(1, new Data.ToPhi(port));
                 final Phi listened = socket.take("listen").copy();
                 listened.put(0, new Server(msg.length()));
@@ -108,7 +99,7 @@ void sendsAndReceivesMessageViaSocketObject() throws InterruptedException, IOExc
         server.start();
         Thread.sleep(2000);
         final Phi socket = Phi.Φ.take("org.eolang.nk.socket").copy();
-        socket.put(0, new Data.ToPhi(EOsocketTest.LOCALHOST));
+        socket.put(0, new Data.ToPhi(this.localhost()));
         socket.put(1, new Data.ToPhi(port));
         final Phi connected = socket.take("connect").copy();
         connected.put(0, new Client(msg));
@@ -126,6 +117,13 @@ void sendsAndReceivesMessageViaSocketObject() throws InterruptedException, IOExc
         );
     }
 
+    /**
+     * Returns the localhost address.
+     */
+    private String localhost() {
+        return "127.0.0.1";
+    }
+
     /**
      * Convert port number from host to network byte order (htons).
      * @param port Port number
@@ -142,7 +140,7 @@ private static short htons(final int port) {
     private static int randomPort() {
         final int min = 10_000;
         final int max = 20_000;
-        return EOsocketTest.RANDOM.nextInt((max - min) + 1) + min;
+        return new Random().nextInt((max - min) + 1) + min;
     }
 
     /**
@@ -500,7 +498,7 @@ private SockaddrIn sockaddr(final int port) throws UnknownHostException {
             return new SockaddrIn(
                 (short) Winsock.AF_INET,
                 EOsocketTest.htons(port),
-                this.inetAddr(EOsocketTest.LOCALHOST)
+                this.inetAddr("127.0.0.1")
             );
         }
     }
@@ -793,7 +791,7 @@ private SockaddrIn sockaddr(final int port) {
             return new SockaddrIn(
                 (short) CStdLib.AF_INET,
                 EOsocketTest.htons(port),
-                this.inetAddr(EOsocketTest.LOCALHOST)
+                this.inetAddr("127.0.0.1")
             );
         }
     }
@@ -824,7 +822,7 @@ RandomServer started() {
                 try {
                     this.socket = new ServerSocket();
                     this.socket.setReuseAddress(true);
-                    this.socket.bind(new InetSocketAddress(EOsocketTest.LOCALHOST, this.port));
+                    this.socket.bind(new InetSocketAddress("127.0.0.1", this.port));
                     bound = true;
                     Logger.debug(this, "Server started on port %d", this.port);
                 } catch (final IOException exception) {
diff --git a/eo-runtime/src/test/java/EOorg/EOeolang/HeapsTest.java b/eo-runtime/src/test/java/EOorg/EOeolang/HeapsTest.java
index f6b92c81a77..ad53010d051 100644
--- a/eo-runtime/src/test/java/EOorg/EOeolang/HeapsTest.java
+++ b/eo-runtime/src/test/java/EOorg/EOeolang/HeapsTest.java
@@ -27,62 +27,58 @@
  */
 @SuppressWarnings("PMD.TooManyMethods")
 final class HeapsTest {
-    /**
-     * Heaps.
-     */
-    private static final Heaps HEAPS = Heaps.INSTANCE;
 
     @Test
     void allocatesMemory() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 10);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 10);
         Assertions.assertDoesNotThrow(
-            () -> HeapsTest.HEAPS.read(idx, 0, 10),
+            () -> Heaps.INSTANCE.read(idx, 0, 10),
             "Heaps should successfully read from allocated memory, but it didn't"
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void failsOnDoubleAllocation() {
         final Phi phi = new HeapsTest.PhFake();
-        final int idx = HeapsTest.HEAPS.malloc(phi, 10);
+        final int idx = Heaps.INSTANCE.malloc(phi, 10);
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.malloc(phi, 10),
+            () -> Heaps.INSTANCE.malloc(phi, 10),
             "Heaps should throw an exception on attempting to allocate already allocated memory, but it didn't"
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void allocatesAndReadsEmptyBytes() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
         MatcherAssert.assertThat(
             "Heaps should return empty bytes after memory allocation, but it didn't",
-            HeapsTest.HEAPS.read(idx, 0, 5),
+            Heaps.INSTANCE.read(idx, 0, 5),
             Matchers.equalTo(new byte[] {0, 0, 0, 0, 0})
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void writesAndReads() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
         final byte[] bytes = {1, 2, 3, 4, 5};
-        HeapsTest.HEAPS.write(idx, 0, bytes);
+        Heaps.INSTANCE.write(idx, 0, bytes);
         MatcherAssert.assertThat(
             "Heaps should successfully read exactly same bytes that were written, but it didn't",
-            HeapsTest.HEAPS.read(idx, 0, bytes.length),
+            Heaps.INSTANCE.read(idx, 0, bytes.length),
             Matchers.equalTo(bytes)
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void failsOnWriteToEmptyBlock() {
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.write(new HeapsTest.PhFake().hashCode(), 0, new byte[] {0x01}),
+            () -> Heaps.INSTANCE.write(new HeapsTest.PhFake().hashCode(), 0, new byte[] {0x01}),
             "Heaps should throw an exception on writing to an unallocated block, but it didn't"
         );
     }
@@ -91,76 +87,76 @@ void failsOnWriteToEmptyBlock() {
     void failsOnReadFromEmptyBlock() {
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.read(new HeapsTest.PhFake().hashCode(), 0, 1),
+            () -> Heaps.INSTANCE.read(new HeapsTest.PhFake().hashCode(), 0, 1),
             "Heaps should throw an exception on reading from an unallocated block, but it didn't"
         );
     }
 
     @Test
     void failsOnReadIfOutOfBounds() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 2);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 2);
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.read(idx, 1, 3),
+            () -> Heaps.INSTANCE.read(idx, 1, 3),
             "Heaps should throw an exception on out-of-bounds read, but it didn't"
         );
     }
 
     @Test
     void readsByOffsetAndLength() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
-        HeapsTest.HEAPS.write(idx, 0, new byte[] {1, 2, 3, 4, 5});
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
+        Heaps.INSTANCE.write(idx, 0, new byte[] {1, 2, 3, 4, 5});
         MatcherAssert.assertThat(
             "Heaps should successfully read correct slice when reading with offset and length, but it didn't",
-            HeapsTest.HEAPS.read(idx, 1, 3),
+            Heaps.INSTANCE.read(idx, 1, 3),
             Matchers.equalTo(new byte[] {2, 3, 4})
         );
     }
 
     @Test
     void failsOnWriteMoreThanAllocated() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 2);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 2);
         final byte[] bytes = {1, 2, 3, 4, 5};
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.write(idx, 0, bytes),
+            () -> Heaps.INSTANCE.write(idx, 0, bytes),
             "Heaps should throw an exception on writing more bytes than allocated size, but it didn't"
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void failsToWriteMoreThanAllocatedWithOffset() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 3);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 3);
         final byte[] bytes = {1, 2, 3};
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.write(idx, 1, bytes),
+            () -> Heaps.INSTANCE.write(idx, 1, bytes),
             "Heaps should throw an exception on writing past allocated block using offset, but it didn't"
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void concatsOnWriteLessThanAllocated() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
-        HeapsTest.HEAPS.write(idx, 0, new byte[] {1, 1, 3, 4, 5});
-        HeapsTest.HEAPS.write(idx, 2, new byte[] {2, 2});
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
+        Heaps.INSTANCE.write(idx, 0, new byte[] {1, 1, 3, 4, 5});
+        Heaps.INSTANCE.write(idx, 2, new byte[] {2, 2});
         MatcherAssert.assertThat(
             "Heaps should return correct bytes after partial overwrite, but it didn't",
-            HeapsTest.HEAPS.read(idx, 0, 5),
+            Heaps.INSTANCE.read(idx, 0, 5),
             Matchers.equalTo(new byte[] {1, 1, 2, 2, 5})
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void freesSuccessfully() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
-        HeapsTest.HEAPS.free(idx);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
+        Heaps.INSTANCE.free(idx);
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.read(idx, 0, 5),
+            () -> Heaps.INSTANCE.read(idx, 0, 5),
             "Heaps should throw an exception on reading from a freed block, but it didn't"
         );
     }
@@ -169,7 +165,7 @@ void freesSuccessfully() {
     void failsOnClearingEmptyBlock() {
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.free(new HeapsTest.PhFake().hashCode()),
+            () -> Heaps.INSTANCE.free(new HeapsTest.PhFake().hashCode()),
             "Heaps should throw an exception on attempting to free a non-existent block, but it didn't"
         );
     }
@@ -178,82 +174,82 @@ void failsOnClearingEmptyBlock() {
     void throwsOnGettingSizeOfEmptyBlock() {
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.size(new HeapsTest.PhFake().hashCode()),
+            () -> Heaps.INSTANCE.size(new HeapsTest.PhFake().hashCode()),
             "Heaps should throw an exception on trying to get size of an empty block, but it didn't"
         );
     }
 
     @Test
     void returnsValidSize() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
         MatcherAssert.assertThat(
             "Heaps should return valid size of allocated block, but it didn't",
-            HeapsTest.HEAPS.size(idx),
+            Heaps.INSTANCE.size(idx),
             Matchers.equalTo(5)
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void throwsOnChangingSizeToNegative() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.resize(idx, -1),
+            () -> Heaps.INSTANCE.resize(idx, -1),
             "Heaps should throw an exception on trying to changing size to negative, but it didn't"
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void throwsOnChangeSizeOfEmtpyBlock() {
         Assertions.assertThrows(
             ExFailure.class,
-            () -> HeapsTest.HEAPS.resize(new HeapsTest.PhFake().hashCode(), 10),
+            () -> Heaps.INSTANCE.resize(new HeapsTest.PhFake().hashCode(), 10),
             "Heaps should throw an exception on changing size of empty block, but it didn't"
         );
     }
 
     @Test
     void increasesSizeSuccessfully() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
         final byte[] bytes = {1, 2, 3, 4, 5};
-        HeapsTest.HEAPS.write(idx, 0, bytes);
-        HeapsTest.HEAPS.resize(idx, 7);
+        Heaps.INSTANCE.write(idx, 0, bytes);
+        Heaps.INSTANCE.resize(idx, 7);
         MatcherAssert.assertThat(
             "Heaps should successfully increase size of allocated block, but it didn't",
-            HeapsTest.HEAPS.read(idx, 0, 7),
+            Heaps.INSTANCE.read(idx, 0, 7),
             Matchers.equalTo(new byte[] {1, 2, 3, 4, 5, 0, 0})
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void decreasesSizeSuccessfully() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
         final byte[] bytes = {1, 2, 3, 4, 5};
-        HeapsTest.HEAPS.write(idx, 0, bytes);
-        HeapsTest.HEAPS.resize(idx, 3);
+        Heaps.INSTANCE.write(idx, 0, bytes);
+        Heaps.INSTANCE.resize(idx, 3);
         MatcherAssert.assertThat(
             "Heaps should successfully decrease size of allocated block, but it didn't",
-            HeapsTest.HEAPS.read(idx, 0, 3),
+            Heaps.INSTANCE.read(idx, 0, 3),
             Matchers.equalTo(new byte[] {1, 2, 3})
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     @Test
     void returnsValidSizeAfterDecreasing() {
-        final int idx = HeapsTest.HEAPS.malloc(new HeapsTest.PhFake(), 5);
+        final int idx = Heaps.INSTANCE.malloc(new HeapsTest.PhFake(), 5);
         final byte[] bytes = {1, 2, 3, 4, 5};
-        HeapsTest.HEAPS.write(idx, 0, bytes);
-        HeapsTest.HEAPS.resize(idx, 3);
+        Heaps.INSTANCE.write(idx, 0, bytes);
+        Heaps.INSTANCE.resize(idx, 3);
         MatcherAssert.assertThat(
             "Heaps should return valid size after decreasing, but it didn't",
-            HeapsTest.HEAPS.size(idx),
+            Heaps.INSTANCE.size(idx),
             Matchers.equalTo(3)
         );
-        HeapsTest.HEAPS.free(idx);
+        Heaps.INSTANCE.free(idx);
     }
 
     /**
diff --git a/eo-runtime/src/test/java/org/eolang/PhDefaultTest.java b/eo-runtime/src/test/java/org/eolang/PhDefaultTest.java
index f8e68cfb27d..f47c23c141a 100644
--- a/eo-runtime/src/test/java/org/eolang/PhDefaultTest.java
+++ b/eo-runtime/src/test/java/org/eolang/PhDefaultTest.java
@@ -19,17 +19,6 @@
  */
 @SuppressWarnings({"PMD.TooManyMethods", "PMD.GodClass"})
 final class PhDefaultTest {
-    /**
-     * Name of attribute.
-     * @since 0.1
-     */
-    private static final String PLUS_ATT = "plus";
-
-    /**
-     * Name of attribute.
-     * @since 0.1
-     */
-    private static final String VOID_ATT = "void";
 
     @Test
     void comparesTwoObjects() {
@@ -70,7 +59,7 @@ void doesNotHaveRhoWhenFormed() {
 
     @Test
     void setsRhoAfterDispatch() {
-        final Phi kid = new PhDefaultTest.Int().take(PhDefaultTest.PLUS_ATT);
+        final Phi kid = new PhDefaultTest.Int().take(this.plus());
         Assertions.assertDoesNotThrow(
             () -> kid.take(Phi.RHO),
             String.format("Kid of should have %s attribute after dispatch", Phi.RHO)
@@ -90,8 +79,8 @@ void doesNotHaveRhoAfterCopying() {
     @Test
     void copiesKid() {
         final Phi phi = new PhDefaultTest.Int();
-        final Phi first = phi.take(PhDefaultTest.PLUS_ATT);
-        final Phi second = phi.copy().take(PhDefaultTest.PLUS_ATT);
+        final Phi first = phi.take(this.plus());
+        final Phi second = phi.copy().take(this.plus());
         MatcherAssert.assertThat(
             "Child attributes should be copied after copying main object",
             first,
@@ -106,9 +95,9 @@ void takesDifferentAbstractKidsEveryDispatch() {
         final Phi phi = new PhDefaultTest.Int();
         MatcherAssert.assertThat(
             "Child attributes should be copied on every dispatch",
-            phi.take(PhDefaultTest.PLUS_ATT),
+            phi.take(this.plus()),
             Matchers.not(
-                Matchers.equalTo(phi.take(PhDefaultTest.PLUS_ATT))
+                Matchers.equalTo(phi.take(this.plus()))
             )
         );
     }
@@ -116,7 +105,7 @@ void takesDifferentAbstractKidsEveryDispatch() {
     @Test
     void hasKidWithSetRhoAfterCopying() {
         final Phi phi = new PhDefaultTest.Int().copy();
-        final Phi plus = phi.take(PhDefaultTest.PLUS_ATT);
+        final Phi plus = phi.take(this.plus());
         Assertions.assertDoesNotThrow(
             () -> plus.take(Phi.RHO),
             String.format(
@@ -141,9 +130,9 @@ void hasDifferentKidsAfterDoubleCopying() {
         final Phi second = first.copy();
         MatcherAssert.assertThat(
             "Child objects after double copying should be different",
-            first.take(PhDefaultTest.PLUS_ATT),
+            first.take(this.plus()),
             Matchers.not(
-                Matchers.equalTo(second.take(PhDefaultTest.PLUS_ATT))
+                Matchers.equalTo(second.take(this.plus()))
             )
         );
     }
@@ -156,15 +145,15 @@ void changesKidRhoAfterSelfCopying() {
             String.format(
                 "%s attribute of original object kid should refer to original object", Phi.RHO
             ),
-            phi.take(PhDefaultTest.PLUS_ATT).take(Phi.RHO),
-            Matchers.not(Matchers.equalTo(copy.take(PhDefaultTest.PLUS_ATT).take(Phi.RHO)))
+            phi.take(this.plus()).take(Phi.RHO),
+            Matchers.not(Matchers.equalTo(copy.take(this.plus()).take(Phi.RHO)))
         );
         MatcherAssert.assertThat(
             String.format(
                 "%s attribute of copied object kid should refer to copied object",
                 Phi.RHO
             ),
-            copy.take(PhDefaultTest.PLUS_ATT).take(Phi.RHO),
+            copy.take(this.plus()).take(Phi.RHO),
             Matchers.equalTo(copy)
         );
     }
@@ -172,7 +161,7 @@ void changesKidRhoAfterSelfCopying() {
     @Test
     void doesNotChangeRhoAfterDirectKidCopying() {
         final Phi phi = new PhDefaultTest.Int();
-        final Phi first = phi.take(PhDefaultTest.PLUS_ATT);
+        final Phi first = phi.take(this.plus());
         final Phi second = first.copy();
         MatcherAssert.assertThat(
             String.format(
@@ -189,7 +178,7 @@ void doesNotChangeRhoAfterDirectKidCopying() {
     @Test
     void doesNotCopyRhoWhileDispatch() {
         final Phi phi = new PhDefaultTest.Int();
-        final Phi plus = phi.take(PhDefaultTest.PLUS_ATT);
+        final Phi plus = phi.take(this.plus());
         MatcherAssert.assertThat(
             String.format("%s attributes should not be copied while dispatch", Phi.RHO),
             plus.take(Phi.RHO),
@@ -203,7 +192,7 @@ void copiesUnsetVoidAttribute() {
         final Phi copy = phi.copy();
         Assertions.assertThrows(
             ExAbstract.class,
-            () -> copy.take(PhDefaultTest.VOID_ATT),
+            () -> copy.take(this.getVoid()),
             "Unset void attribute should be copied with unset value"
         );
     }
@@ -211,13 +200,13 @@ void copiesUnsetVoidAttribute() {
     @Test
     void copiesSetVoidAttributeOnCopy() {
         final Phi phi = new PhDefaultTest.Int();
-        phi.put(PhDefaultTest.VOID_ATT, new Data.ToPhi(10L));
+        phi.put(this.getVoid(), new Data.ToPhi(10L));
         final Phi copy = phi.copy();
         MatcherAssert.assertThat(
             "Copied set void attribute should be different from original one",
-            phi.take(PhDefaultTest.VOID_ATT),
+            phi.take(this.getVoid()),
             Matchers.not(
-                Matchers.equalTo(copy.take(PhDefaultTest.VOID_ATT))
+                Matchers.equalTo(copy.take(this.getVoid()))
             )
         );
     }
@@ -225,11 +214,11 @@ void copiesSetVoidAttributeOnCopy() {
     @Test
     void doesNotCopySetVoidAttributeWithRho() {
         final Phi phi = new PhDefaultTest.Int();
-        phi.put(PhDefaultTest.VOID_ATT, new Data.ToPhi(10L));
+        phi.put(this.getVoid(), new Data.ToPhi(10L));
         MatcherAssert.assertThat(
             "Void attribute should not be copied with rho, but it did",
-            phi.take(PhDefaultTest.VOID_ATT),
-            Matchers.equalTo(phi.take(PhDefaultTest.VOID_ATT))
+            phi.take(this.getVoid()),
+            Matchers.equalTo(phi.take(this.getVoid()))
         );
     }
 
@@ -251,7 +240,7 @@ void hasAccessToDependentOnContextAttribute() {
             () -> phi.take(Phi.PHI),
             "Phi should not be accessible without setting void attribute, but it did"
         );
-        phi.put(PhDefaultTest.VOID_ATT, new Data.ToPhi(10L));
+        phi.put(this.getVoid(), new Data.ToPhi(10L));
         Assertions.assertDoesNotThrow(
             () -> phi.take(Phi.PHI),
             "Phi should be accessible after setting void attribute, but it didn't"
@@ -412,7 +401,7 @@ void hasDifferentFormaWithBoundedMethod() {
             Matchers.not(
                 Matchers.equalTo(
                     new PhWith(
-                        five.take(PhDefaultTest.PLUS_ATT).copy(),
+                        five.take(this.plus()).copy(),
                         "x",
                         new Data.ToPhi(5)
                     ).forma()
@@ -426,13 +415,13 @@ void hasTheSameFormaWithDifferentInstances() {
         MatcherAssert.assertThat(
             "Similar Phis with different data should have the same forma, but they didn't",
             new PhWith(
-                new Data.ToPhi(5L).take(PhDefaultTest.PLUS_ATT).copy(),
+                new Data.ToPhi(5L).take(this.plus()).copy(),
                 "x",
                 new Data.ToPhi(5L)
             ).forma(),
             Matchers.equalTo(
                 new PhWith(
-                    new Data.ToPhi(6L).take(PhDefaultTest.PLUS_ATT).copy(),
+                    new Data.ToPhi(6L).take(this.plus()).copy(),
                     "x",
                     new Data.ToPhi(6L)
                 ).forma()
@@ -457,11 +446,11 @@ void doesNotCalculateRandomTwice() {
             new PhMethod(
                 new PhWith(
                     new PhMethod(
-                        new Rnd(), PhDefaultTest.PLUS_ATT
+                        new Rnd(), this.plus()
                     ),
                     0, new Data.ToPhi(1.2)
                 ),
-                PhDefaultTest.PLUS_ATT
+                this.plus()
             ),
             0, new Data.ToPhi(1.2)
         );
@@ -574,6 +563,20 @@ private Phi phiWithContextAttribute(final String attribute) {
         return phi;
     }
 
+    /**
+     * Returns the 'plus' literal.
+     */
+    private String plus() {
+        return "plus";
+    }
+
+    /**
+     * Returns the 'void' literal.
+     */
+    private String getVoid() {
+        return "void";
+    }
+
     @SuppressWarnings("PMD.AvoidAccessibilityAlteration")
     private static void cleansUpNesting() {
         try {
@@ -617,14 +620,14 @@ private static class Int extends PhDefault {
          */
         @SuppressWarnings("PMD.ConstructorOnlyInitializesOrCallOtherConstructors")
         Int() {
-            this.add(PhDefaultTest.VOID_ATT, new PhVoid(PhDefaultTest.VOID_ATT));
-            this.add(PhDefaultTest.PLUS_ATT, new PhSimple(new PhDefault()));
+            this.add("void", new PhVoid("void"));
+            this.add("plus", new PhSimple(new PhDefault()));
             this.add(
                 Phi.PHI,
                 new PhCached(
                     new PhComposite(
                         this,
-                        rho -> rho.take(PhDefaultTest.VOID_ATT)
+                        rho -> rho.take("void")
                     )
                 )
             );
@@ -635,7 +638,7 @@ private static class Int extends PhDefault {
                         this,
                         rho -> {
                             final Phi plus = new Data.ToPhi(5L).take(
-                                PhDefaultTest.PLUS_ATT
+                                "plus"
                             ).copy();
                             plus.put(0, new Data.ToPhi(6L));
                             return plus;
diff --git a/eo-runtime/src/test/java/org/eolang/PhPackageTest.java b/eo-runtime/src/test/java/org/eolang/PhPackageTest.java
index 7f46a68bff4..48bca2f634c 100644
--- a/eo-runtime/src/test/java/org/eolang/PhPackageTest.java
+++ b/eo-runtime/src/test/java/org/eolang/PhPackageTest.java
@@ -24,11 +24,6 @@
 @SuppressWarnings("PMD.TooManyMethods")
 final class PhPackageTest {
 
-    /**
-     * Default test package.
-     */
-    private static final String DEFAULT_PACKAGE = "Φ.org.eolang";
-
     @Test
     void copiesObject() {
         MatcherAssert.assertThat(
@@ -94,7 +89,7 @@ void findsLongClass() {
     @ParameterizedTest
     @MethodSource("attributes")
     void retrievesAttribute(final String attribute, final Class<?> expected) {
-        final Phi parent = new PhPackage(PhPackageTest.DEFAULT_PACKAGE);
+        final Phi parent = new PhPackage(this.phiPackageName());
         final Phi actual = parent.take(attribute);
         MatcherAssert.assertThat(
             String.format(
@@ -110,14 +105,14 @@ void retrievesAttribute(final String attribute, final Class<?> expected) {
     void throwsExceptionIfCantInstantiateObject() {
         Assertions.assertThrows(
             ExFailure.class,
-            () -> new PhPackage(PhPackageTest.DEFAULT_PACKAGE).take("failed"),
+            () -> new PhPackage(this.phiPackageName()).take("failed"),
             "Should throw if object cannot be instantiated, but it was"
         );
     }
 
     @Test
     void returnsSelfOnCopy() {
-        final Phi pckg = new PhPackage(PhPackageTest.DEFAULT_PACKAGE);
+        final Phi pckg = new PhPackage(this.phiPackageName());
         MatcherAssert.assertThat(
             "Package object should return itself on copying",
             pckg.copy(),
@@ -129,8 +124,8 @@ void returnsSelfOnCopy() {
     void returnsForma() {
         MatcherAssert.assertThat(
             "Should return valid forma",
-            new PhPackage(PhPackageTest.DEFAULT_PACKAGE).forma(),
-            Matchers.equalTo(PhPackageTest.DEFAULT_PACKAGE)
+            new PhPackage(this.phiPackageName()).forma(),
+            Matchers.equalTo(this.phiPackageName())
         );
     }
 
@@ -138,14 +133,14 @@ void returnsForma() {
     void returnsLocator() {
         MatcherAssert.assertThat(
             "locator of the DEFAULT_PACKAGE must be ?:?:?, but is wasn't",
-            new PhPackage(PhPackageTest.DEFAULT_PACKAGE).locator(),
+            new PhPackage(this.phiPackageName()).locator(),
             Matchers.equalTo("?:?:?")
         );
     }
 
     @Test
     void findsAttributesInThreads() {
-        final PhPackage pckg = new PhPackage(PhPackageTest.DEFAULT_PACKAGE);
+        final PhPackage pckg = new PhPackage(this.phiPackageName());
         MatcherAssert.assertThat(
             "Should take an attribute in multiple threads",
             new Together<>(
@@ -157,6 +152,13 @@ void findsAttributesInThreads() {
         );
     }
 
+    /**
+     * Returns the phi package name.
+     */
+    private String phiPackageName() {
+        return "Φ.org.eolang";
+    }
+
     private static Stream<Arguments> attributes() {
         return Stream.of(
             Arguments.of("bytes$eq", EObytes$EOeq.class),
diff --git a/pom.xml b/pom.xml
index 84bd40944e4..ba43bbca2ec 100644
--- a/pom.xml
+++ b/pom.xml
@@ -502,7 +502,7 @@
           <plugin>
             <groupId>com.github.volodya-lombrozo</groupId>
             <artifactId>jtcop-maven-plugin</artifactId>
-            <version>1.3.5</version>
+            <version>1.4.1</version>
             <configuration>
               <ignoreGeneratedTests>true</ignoreGeneratedTests>
             </configuration>