1 files changed, 103 insertions, 0 deletions
diff --git a/impl_core/src/test/java/io/opencensus/implcore/tags/CurrentTagContextUtilsTest.java b/impl_core/src/test/java/io/opencensus/implcore/tags/CurrentTagContextUtilsTest.java
new file mode 100644
index 00000000..1a14ac6e
--- /dev/null
+++ b/impl_core/src/test/java/io/opencensus/implcore/tags/CurrentTagContextUtilsTest.java
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2017, OpenCensus Authors
+ *
+ * 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.
+ */
+
+package io.opencensus.implcore.tags;
+
+import static com.google.common.truth.Truth.assertThat;
+import static io.opencensus.implcore.tags.TagsTestUtil.tagContextToList;
+
+import com.google.common.collect.ImmutableSet;
+import io.grpc.Context;
+import io.opencensus.common.Scope;
+import io.opencensus.tags.Tag;
+import io.opencensus.tags.TagContext;
+import io.opencensus.tags.TagKey;
+import io.opencensus.tags.TagValue;
+import io.opencensus.tags.unsafe.ContextUtils;
+import java.util.Iterator;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Unit tests for {@link CurrentTagContextUtils}. */
+@RunWith(JUnit4.class)
+public class CurrentTagContextUtilsTest {
+  private static final Tag TAG = Tag.create(TagKey.create("key"), TagValue.create("value"));
+
+  private final TagContext tagContext =
+      new TagContext() {
+
+        @Override
+        protected Iterator<Tag> getIterator() {
+          return ImmutableSet.<Tag>of(TAG).iterator();
+        }
+      };
+
+  @Test
+  public void testGetCurrentTagContext_DefaultContext() {
+    TagContext tags = CurrentTagContextUtils.getCurrentTagContext();
+    assertThat(tags).isNotNull();
+    assertThat(tagContextToList(tags)).isEmpty();
+  }
+
+  @Test
+  public void testGetCurrentTagContext_ContextSetToNull() {
+    Context orig = Context.current().withValue(ContextUtils.TAG_CONTEXT_KEY, null).attach();
+    try {
+      TagContext tags = CurrentTagContextUtils.getCurrentTagContext();
+      assertThat(tags).isNotNull();
+      assertThat(tagContextToList(tags)).isEmpty();
+    } finally {
+      Context.current().detach(orig);
+    }
+  }
+
+  @Test
+  public void testWithTagContext() {
+    assertThat(tagContextToList(CurrentTagContextUtils.getCurrentTagContext())).isEmpty();
+    Scope scopedTags = CurrentTagContextUtils.withTagContext(tagContext);
+    try {
+      assertThat(CurrentTagContextUtils.getCurrentTagContext()).isSameAs(tagContext);
+    } finally {
+      scopedTags.close();
+    }
+    assertThat(tagContextToList(CurrentTagContextUtils.getCurrentTagContext())).isEmpty();
+  }
+
+  @Test
+  public void testWithTagContextUsingWrap() {
+    Runnable runnable;
+    Scope scopedTags = CurrentTagContextUtils.withTagContext(tagContext);
+    try {
+      assertThat(CurrentTagContextUtils.getCurrentTagContext()).isSameAs(tagContext);
+      runnable =
+          Context.current()
+              .wrap(
+                  new Runnable() {
+                    @Override
+                    public void run() {
+                      assertThat(CurrentTagContextUtils.getCurrentTagContext())
+                          .isSameAs(tagContext);
+                    }
+                  });
+    } finally {
+      scopedTags.close();
+    }
+    assertThat(tagContextToList(CurrentTagContextUtils.getCurrentTagContext())).isEmpty();
+    // When we run the runnable we will have the TagContext in the current Context.
+    runnable.run();
+  }
+}