Simplify API required to call methods by reflection. (#45)

* Implement a cleaner way to call methods by reflection.
* Port all callers to the new reflection API.

1 files changed, 120 insertions, 0 deletions

diff --git a/src/test/java/UtilsTest.java b/src/test/java/UtilsTest.java
new file mode 100644
index 0000000..b9a70d2
--- /dev/null
+++ b/src/test/java/UtilsTest.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+import static com.google.android.mobly.snippet.bundled.utils.Utils.invokeByReflection;
+
+import com.google.android.mobly.snippet.bundled.utils.Utils;
+import com.google.common.truth.Truth;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import org.junit.Assert;
+import org.junit.Test;
+
+/** Tests for {@link com.google.android.mobly.snippet.bundled.utils.Utils} */
+public class UtilsTest {
+    public static final class ReflectionTest_HostClass {
+        public Object returnSame(List<String> arg) {
+            return arg;
+        }
+
+        public Object returnSame(int arg) {
+            return arg;
+        }
+
+        public Object multiArgCall(Object arg1, Object arg2, boolean returnArg1) {
+            if (returnArg1) {
+                return arg1;
+            }
+            return arg2;
+        }
+
+        public boolean returnTrue() {
+            return true;
+        }
+
+        public void throwsException() throws IOException {
+            throw new IOException("Example exception");
+        }
+    }
+
+    @Test
+    public void testInvokeByReflection_Obj() throws Throwable {
+        List<?> sampleList = Collections.singletonList("sampleList");
+        ReflectionTest_HostClass hostClass = new ReflectionTest_HostClass();
+        Object ret = invokeByReflection(hostClass, "returnSame", sampleList);
+        Truth.assertThat(ret).isSameAs(sampleList);
+    }
+
+    @Test
+    public void testInvokeByReflection_Null() throws Throwable {
+        ReflectionTest_HostClass hostClass = new ReflectionTest_HostClass();
+        Object ret = invokeByReflection(hostClass, "returnSame", (Object) null);
+        Truth.assertThat(ret).isNull();
+    }
+
+    @Test
+    public void testInvokeByReflection_NoArg() throws Throwable {
+        ReflectionTest_HostClass hostClass = new ReflectionTest_HostClass();
+        boolean ret = (boolean) invokeByReflection(hostClass, "returnTrue");
+        Truth.assertThat(ret).isTrue();
+    }
+
+    @Test
+    public void testInvokeByReflection_Primitive() throws Throwable {
+        ReflectionTest_HostClass hostClass = new ReflectionTest_HostClass();
+        Object ret = invokeByReflection(hostClass, "returnSame", 5);
+        Truth.assertThat(ret).isEqualTo(5);
+    }
+
+    @Test
+    public void testInvokeByReflection_MultiArg() throws Throwable {
+        ReflectionTest_HostClass hostClass = new ReflectionTest_HostClass();
+        Object arg1 = new Object();
+        Object arg2 = new Object();
+        Object ret =
+                invokeByReflection(hostClass, "multiArgCall", arg1, arg2, true /* returnArg1 */);
+        Truth.assertThat(ret).isSameAs(arg1);
+        ret =
+                Utils.invokeByReflection(
+                        hostClass, "multiArgCall", arg1, arg2, false /* returnArg1 */);
+        Truth.assertThat(ret).isSameAs(arg2);
+    }
+
+    @Test
+    public void testInvokeByReflection_NoMatch() throws Throwable {
+        ReflectionTest_HostClass hostClass = new ReflectionTest_HostClass();
+        Truth.assertThat(List.class.isAssignableFrom(Object.class)).isFalse();
+        try {
+            invokeByReflection(hostClass, "returnSame", new Object());
+            Assert.fail();
+        } catch (NoSuchMethodException e) {
+            Truth.assertThat(e.getMessage())
+                    .contains("UtilsTest$ReflectionTest_HostClass#returnSame(Object)");
+        }
+    }
+
+    @Test
+    public void testInvokeByReflection_UnwrapException() throws Throwable {
+        ReflectionTest_HostClass hostClass = new ReflectionTest_HostClass();
+        try {
+            invokeByReflection(hostClass, "throwsException");
+            Assert.fail();
+        } catch (IOException e) {
+            Truth.assertThat(e.getMessage()).isEqualTo("Example exception");
+        }
+    }
+}