Add lenient option for whenever (#454)

With this, we have fully fixed #325

Author: taeyeon-Kim

mockito-kotlin/src/main/kotlin/org/mockito/kotlin/LenientStubber.kt

@@ -0,0 +1,38 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2018 Niek Haarman
+ * Copyright (c) 2007 Mockito contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package org.mockito.kotlin
+
+import org.mockito.stubbing.LenientStubber
+import org.mockito.stubbing.OngoingStubbing
+
+inline fun <reified T : Any> LenientStubber.whenever(methodCall: T): OngoingStubbing<T> {
+    return `when`(methodCall)
+}
+
+inline fun <reified T : Any> LenientStubber.whenever(methodCall: () -> T): OngoingStubbing<T> {
+    return whenever(methodCall())
+}
+

tests/src/test/kotlin/test/LenientStubberTest.kt

@@ -0,0 +1,37 @@
+package test
+
+import org.junit.Assert
+import org.junit.Rule
+import org.junit.Test
+import org.mockito.Mockito.lenient
+import org.mockito.junit.MockitoJUnit
+import org.mockito.junit.MockitoRule
+import org.mockito.kotlin.any
+import org.mockito.kotlin.doReturn
+import org.mockito.kotlin.mock
+import org.mockito.kotlin.whenever
+import org.mockito.quality.Strictness
+
+
+open class LenientStubberTest {
+    @get:Rule
+    val rule: MockitoRule = MockitoJUnit.rule().strictness(Strictness.STRICT_STUBS)
+
+    @Test
+    fun unused_and_lenient_stubbings() {
+        val mock = mock<MutableList<String>>()
+        lenient().whenever(mock.add("one")).doReturn(true)
+        whenever(mock[any()]).doReturn("hello")
+
+        Assert.assertEquals("List should contain hello", "hello", mock[1])
+    }
+
+    @Test
+    fun unused_and_lenient_stubbings_with_unit() {
+        val mock = mock<MutableList<String>>()
+        lenient().whenever { mock.add("one") }.doReturn(true)
+        whenever(mock[any()]).doReturn("hello")
+
+        Assert.assertEquals("List should contain hello", "hello", mock[1])
+    }
+}