Fixes Issue #256

Author: ultrasecreth

common/src/main/scala/org/mockito/matchers/ThatMatchers.scala

@@ -1,6 +1,8 @@
 package org.mockito.matchers
 
-import org.mockito.{ ArgumentMatcher, ArgumentMatchers => JavaMatchers }
+import org.mockito.{ArgumentMatcher, ArgumentMatchers => JavaMatchers}
+
+import scala.util.Try
 
 private[mockito] trait ThatMatchers {
 
@@ -16,7 +18,7 @@ private[mockito] trait ThatMatchers {
    */
   def argThat[T](f: T => Boolean, desc: => String = "argThat(<condition>)"): T =
     JavaMatchers.argThat(new ArgumentMatcher[T] with Serializable {
-      override def matches(argument: T): Boolean = f(argument)
+      override def matches(argument: T): Boolean = Try(f(argument)).fold(_ => false, identity)
       override def toString: String              = desc
     })
 

scalatest/src/test/scala/user/org/mockito/Issue256.scala

@@ -0,0 +1,29 @@
+package user.org.mockito
+
+import org.scalatest.matchers.should.Matchers
+import org.scalatest.wordspec.AnyWordSpec
+import org.mockito.{ ArgumentMatchersSugar, IdiomaticMockito, MockitoScalaSession }
+import IdiomaticMockito._
+import ArgumentMatchersSugar._
+
+
+
+class Issue256 extends AnyWordSpec with Matchers{
+
+  trait Foo {
+    def test[A](a: A): A
+  }
+
+  "mockito" should {
+    "allow stubbing the same method multiple times" in {
+      MockitoScalaSession().run {
+        val foo = mock[Foo]
+        foo.test[String](argThat((s: String) => s.startsWith("foo"))) returns "foo"
+        foo.test[Int](argThat((n: Int) => n > 10)) returns 42
+
+        foo.test("fooSSS") shouldBe "foo"
+        foo.test(11) shouldBe 42
+      }
+    }
+  }
+}