Create PalindromeProductsTestGenerator.scala. Update PalindromeProduc…

config.json

@@ -746,6 +746,7 @@
       "unlocked_by": "sum-of-multiples",
       "difficulty": 6,
       "topics": [
+        "Optional values",
         "Sets",
         "Strings",
         "Tuples",

exercises/palindrome-products/example.scala

@@ -1,12 +1,15 @@
 
 case class PalindromeProducts(minFactor: Int, maxFactor: Int) {
 
-  lazy val (smallest: (Int, Set[(Int, Int)]),
-            largest: (Int, Set[(Int, Int)])) = {
+  lazy val (smallest: Option[(Int, Set[(Int, Int)])],
+            largest: Option[(Int, Set[(Int, Int)])]) = {
     val palindromes = for (a <- Range(minFactor, maxFactor + 1);
-         b <- Range(a, maxFactor + 1) if isPalindrome(a * b)) yield (a * b, (a, b))
+                           b <- Range(a, maxFactor + 1) if isPalindrome(a * b)) yield (a * b, (a, b))
     val mapped = palindromes.groupBy(_._1).map{case(k, v) => (k, v.map(_._2).toSet)}
-    (mapped.minBy(_._1), mapped.maxBy(_._1))
+    if (mapped.isEmpty)
+      (None, None)
+    else
+      (Some(mapped.minBy(_._1)), Some(mapped.maxBy(_._1)))
   }
 
   private def isPalindrome(i: Int) = i.toString == i.toString.reverse

exercises/palindrome-products/src/test/scala/PalindromeProductsTest.scala

@@ -1,59 +1,79 @@
-import org.scalatest.{Matchers, FlatSpec}
+import org.scalatest.{Matchers, FunSuite}
 
-class PalindromeProductsTest extends FlatSpec with Matchers {
+/** @version 1.0.0 */
+class PalindromeProductsTest extends FunSuite with Matchers {
 
-  it should "find smallest palindrome from a single digit factors" in {
-    val (value, factors) = PalindromeProducts(1, 9).smallest
-    value should be (1)
-    factors should be (Set((1, 1)))
+  // PalindromeProducts largest call is expecting a return type of
+  // Option[(Int, Set[(Int, Int)])] - None is expected for error cases.
+  // Some is expected for valid cases. The first element of the tuple
+  // is the largest palindrome product value. The second element of the
+  // tuple is the list of factors.
+  // PalindromeProducts smallest call is expecting a return type of
+  // Option[(Int, Set[(Int, Int)])] - None is expected for error cases.
+  // Some is expected for valid cases. The first element of the tuple
+  // is the smallest palindrome product value. The second element of the
+  // tuple is the list of factors.
+
+  test("finds the smallest palindrome from single digit factors") {
+    PalindromeProducts(1, 9).smallest should be(Some((1, Set((1, 1)))))
+  }
+
+  test("finds the largest palindrome from single digit factors") {
+    pending
+    PalindromeProducts(1, 9).largest should be(Some((9, Set((1, 9), (3, 3)))))
+  }
+
+  test("find the smallest palindrome from double digit factors") {
+    pending
+    PalindromeProducts(10, 99).smallest should be(Some((121, Set((11, 11)))))
+  }
+
+  test("find the largest palindrome from double digit factors") {
+    pending
+    PalindromeProducts(10, 99).largest should be(Some((9009, Set((91, 99)))))
+  }
+
+  test("find smallest palindrome from triple digit factors") {
+    pending
+    PalindromeProducts(100, 999).smallest should be(
+      Some((10201, Set((101, 101)))))
   }
 
-  it should "find largest palindrome from a single digit factors" in {
+  test("find the largest palindrome from triple digit factors") {
     pending
-    val (value, factors) = PalindromeProducts(0, 9).largest
-    value should be (9)
-    factors should be (Set((1, 9), (3, 3)))
+    PalindromeProducts(100, 999).largest should be(
+      Some((906609, Set((913, 993)))))
   }
 
-  it should "find smallest palindrome from a double digit factors" in {
+  test("find smallest palindrome from four digit factors") {
     pending
-    val (value, factors) = PalindromeProducts(10, 99).smallest
-    value should be (121)
-    factors should be (Set((11, 11)))
+    PalindromeProducts(1000, 9999).smallest should be(
+      Some((1002001, Set((1001, 1001)))))
   }
 
-  it should "find largest palindrome from a double digit factors" in {
+  test("find the largest palindrome from four digit factors") {
     pending
-    val (value, factors) = PalindromeProducts(10, 99).largest
-    value should be (9009)
-    factors should be (Set((91, 99)))
+    PalindromeProducts(1000, 9999).largest should be(
+      Some((99000099, Set((9901, 9999)))))
   }
 
-  it should "find smallest palindrome from a triple digit factors" in {
+  test("empty result for smallest if no palindrome in the range") {
     pending
-    val (value, factors) = PalindromeProducts(100, 999).smallest
-    value should be (10201)
-    factors should be (Set((101, 101)))
+    PalindromeProducts(1002, 1003).smallest should be(None)
   }
 
-  it should "find largest palindrome from a triple digit factors" in {
+  test("empty result for largest if no palindrome in the range") {
     pending
-    val (value, factors) = PalindromeProducts(100, 999).largest
-    value should be (906609)
-    factors should be (Set((913, 993)))
+    PalindromeProducts(15, 15).largest should be(None)
   }
 
-  it should "find smallest palindrome from a four digit factors" in {
+  test("error result for smallest if min is more than max") {
     pending
-    val (value, factors) = PalindromeProducts(1000, 9999).smallest
-    value should be (1002001)
-    factors should be (Set((1001, 1001)))
+    PalindromeProducts(10000, 1).smallest should be(None)
   }
 
-  it should "find largest palindrome from a four digit factors" in {
+  test("error result for largest if min is more than max") {
     pending
-    val (value, factors) = PalindromeProducts(1000, 9999).largest
-    value should be (99000099)
-    factors should be (Set((9901, 9999)))
+    PalindromeProducts(2, 1).largest should be(None)
   }
 }

testgen/src/main/scala/PalindromeProductsTestGenerator.scala

@@ -0,0 +1,50 @@
+import java.io.File
+
+import testgen.TestSuiteBuilder.{toString, _}
+import testgen._
+
+object PalindromeProductsTestGenerator {
+  def main(args: Array[String]): Unit = {
+    val file = new File("src/main/resources/palindrome-products.json")
+
+    def toStringFromMap(m: Map[String, Any]): String =
+      s"Some((${m("value").toString}, " +
+        s"Set(${m("factors").asInstanceOf[List[List[Int]]].map(xs => "(" + xs.map(_.toString).mkString(", ") + ")").mkString(", ")})))"
+
+
+    def toString(expected: CanonicalDataParser.Expected): String = {
+      expected match {
+        case Left(_) => "None"
+        case Right(m: Map[String, any]) => toStringFromMap(m)
+      }
+    }
+
+    def fromLabeledTest(argNames: String*): ToTestCaseData =
+      withLabeledTest { sut =>
+        labeledTest =>
+          val args = sutArgs(labeledTest.result, argNames: _*)
+          val property = labeledTest.property
+          val sutCall = s"""$sut($args).$property"""
+          val expected = toString(labeledTest.expected)
+          TestCaseData(labeledTest.description, sutCall, expected)
+      }
+
+    val code =
+      TestSuiteBuilder.build(file, fromLabeledTest("input_min", "input_max"),
+        Seq(),
+        Seq("// PalindromeProducts largest call is expecting a return type of",
+            "// Option[(Int, Set[(Int, Int)])] - None is expected for error cases.",
+            "// Some is expected for valid cases. The first element of the tuple ",
+            "// is the largest palindrome product value. The second element of the",
+            "// tuple is the list of factors.",
+            "// PalindromeProducts smallest call is expecting a return type of",
+            "// Option[(Int, Set[(Int, Int)])] - None is expected for error cases.",
+            "// Some is expected for valid cases. The first element of the tuple ",
+            "// is the smallest palindrome product value. The second element of the",
+            "// tuple is the list of factors."))
+
+    println(s"-------------")
+    println(code)
+    println(s"-------------")
+  }
+}