Add tests for java jni bindings

Summary: Add tests for java jni integration

Reviewed By: lucasr

Differential Revision: D4008411

fbshipit-source-id: c896a3925ff3f7fa368176a3d03c84eb7188ef60

java/BUCK

@@ -43,3 +43,14 @@ java_library(
   ],
   visibility = ['PUBLIC'],
 )
+
+java_test(
+  name = 'tests',
+  srcs = glob(['tests/**/*.java']),
+  deps = [
+    ':java',
+    JUNIT_TARGET,
+  ],
+  use_cxx_libraries = True,
+  cxx_library_whitelist = CXX_LIBRARY_WHITELIST,
+)

java/com/facebook/csslayout/CSSNode.java

@@ -29,6 +29,11 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
     }
   }
 
+  /**
+   * Get native instance count. Useful for testing only.
+   */
+  static native int jni_CSSNodeGetInstanceCount();
+
   private CSSNode mParent;
   private List<CSSNode> mChildren;
   private MeasureFunction mMeasureFunction;

java/jni/CSSJNI.cpp

@@ -41,6 +41,10 @@ static inline CSSNodeRef _jlong2CSSNodeRef(jlong addr) {
   return reinterpret_cast<CSSNodeRef>(static_cast<intptr_t>(addr));
 }
 
+jint jni_CSSNodeGetInstanceCount(alias_ref<jclass> clazz) {
+  return CSSNodeGetInstanceCount();
+}
+
 jlong jni_CSSNodeNew(alias_ref<jobject> thiz) {
   const CSSNodeRef node = CSSNodeNew();
   auto globalThiz = make_global(thiz);
@@ -234,6 +238,8 @@ jint JNI_OnLoad(JavaVM *vm, void *) {
                         CSSMakeNativeMethod(jni_CSSNodeLayoutGetWidth),
                         CSSMakeNativeMethod(jni_CSSNodeLayoutGetHeight),
                         CSSMakeNativeMethod(jni_CSSNodeLayoutGetDirection),
+
+                        CSSMakeNativeMethod(jni_CSSNodeGetInstanceCount),
                     });
   });
 }

java/tests/com/facebook/csslayout/CSSNodeTest.java

@@ -0,0 +1,61 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+package com.facebook.csslayout;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class CSSNodeTest {
+
+  @Test
+  public void testInit() {
+    final int refCount = CSSNode.jni_CSSNodeGetInstanceCount();
+    final CSSNode node = new CSSNode();
+    assertEquals(refCount + 1, CSSNode.jni_CSSNodeGetInstanceCount());
+  }
+
+  @Test
+  public void testFree() {
+    final int refCount = CSSNode.jni_CSSNodeGetInstanceCount();
+    final CSSNode node = new CSSNode();
+    node.free();
+    assertEquals(refCount, CSSNode.jni_CSSNodeGetInstanceCount());
+  }
+
+  @Test
+  public void testReinit() {
+    final int refCount = CSSNode.jni_CSSNodeGetInstanceCount();
+    final CSSNode node = new CSSNode();
+    node.free();
+    node.reinit();
+    assertEquals(refCount + 1, CSSNode.jni_CSSNodeGetInstanceCount());
+  }
+
+  @Test
+  public void testMeasure() {
+    final CSSNode node = new CSSNode();
+    node.setMeasureFunction(new CSSNodeAPI.MeasureFunction() {
+        public void measure(
+            CSSNodeAPI node,
+            float width,
+            CSSMeasureMode widthMode,
+            float height,
+            CSSMeasureMode heightMode,
+            MeasureOutput measureOutput) {
+          measureOutput.width = 100;
+          measureOutput.height = 100;
+        }
+    });
+    node.calculateLayout(null);
+    assertEquals(100, (int) node.getLayoutWidth());
+    assertEquals(100, (int) node.getLayoutHeight());
+  }
+}