add tests for the argThat(matcher: ArgumentMatcher<T>) function

Author: sothawo

tests/src/test/kotlin/test/VarArgMatcherTest.kt

@@ -0,0 +1,68 @@
+package test
+
+import com.nhaarman.expect.expect
+import com.nhaarman.mockitokotlin2.argThat
+import com.nhaarman.mockitokotlin2.mock
+import com.nhaarman.mockitokotlin2.whenever
+import org.junit.Test
+import org.mockito.ArgumentMatcher
+import org.mockito.internal.matchers.VarargMatcher
+import org.mockito.invocation.InvocationOnMock
+import org.mockito.stubbing.Answer
+
+/**
+ *
+ */
+class VarArgMatcherTest : TestBase() {
+
+    @Test
+    fun testVarargAnySuccess() {
+        val t = mock<Tested>()
+
+        // a matcher to check if any of the varargs was equals to "b"
+        val matcher = VarargAnyMatcher<String, Boolean>({ "b" == it }, true, false)
+
+        whenever(t.something(argThat(matcher))).thenAnswer(matcher)
+
+        assert(t.something("a", "b", "c"))
+    }
+
+    @Test
+    fun testVarargAnyFail() {
+        val t = mock<Tested>()
+
+        // a matcher to check if any of the varargs was equals to "d"
+        val matcher = VarargAnyMatcher<String, Boolean>({ "d" == it }, true, false)
+
+        whenever(t.something(argThat(matcher))).thenAnswer(matcher)
+
+        assert(!t.something("a", "b", "c"))
+    }
+
+    /**
+     * a test class with a vararg function to test
+     */
+    interface Tested {
+        fun something(vararg values: String): Boolean
+    }
+
+    /**
+     * a VarargMatcher implementation for varargs of type [T] that will answer with type [R] if any of the var args
+     * matched. Needs to keep state between matching invocations.
+     */
+    private class VarargAnyMatcher<T, R>(
+        private val match: ((T) -> Boolean),
+        private val success: R,
+        private val failure: R
+    ) : ArgumentMatcher<T>, VarargMatcher, Answer<R> {
+        private var anyMatched = false
+
+        override fun matches(t: T): Boolean {
+            anyMatched = anyMatched or match(t)
+            return true
+        }
+
+        override fun answer(i: InvocationOnMock) = if (anyMatched) success else failure
+    }
+
+}