1 files changed, 57 insertions, 0 deletions
diff --git a/impl_core/src/test/java/io/opencensus/implcore/internal/CurrentStateTest.java b/impl_core/src/test/java/io/opencensus/implcore/internal/CurrentStateTest.java
new file mode 100644
index 00000000..b7e6a93a
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+++ b/impl_core/src/test/java/io/opencensus/implcore/internal/CurrentStateTest.java
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2018, 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.internal;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import io.opencensus.implcore.internal.CurrentState.State;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link CurrentState}. */
+@RunWith(JUnit4.class)
+public final class CurrentStateTest {
+
+  @Rule public final ExpectedException thrown = ExpectedException.none();
+
+  @Test
+  public void defaultState() {
+    assertThat(new CurrentState(State.ENABLED).get()).isEqualTo(State.ENABLED);
+  }
+
+  @Test
+  public void setState() {
+    CurrentState currentState = new CurrentState(State.ENABLED);
+    assertThat(currentState.set(State.DISABLED)).isTrue();
+    assertThat(currentState.getInternal()).isEqualTo(State.DISABLED);
+    assertThat(currentState.set(State.ENABLED)).isTrue();
+    assertThat(currentState.getInternal()).isEqualTo(State.ENABLED);
+    assertThat(currentState.set(State.ENABLED)).isFalse();
+  }
+
+  @Test
+  public void preventSettingStateAfterReadingState() {
+    CurrentState currentState = new CurrentState(State.ENABLED);
+    currentState.get();
+    thrown.expect(IllegalStateException.class);
+    thrown.expectMessage("State was already read, cannot set state.");
+    currentState.set(State.DISABLED);
+  }
+}