Remove usages of Guava Precondtions from opencensus-api (issue #1081).

This commit replaces the most commonly used precondtion checks with methods in
a new utility class, io.opencensus.internal.Utils.

1 files changed, 88 insertions, 0 deletions

diff --git a/api/src/test/java/io/opencensus/internal/UtilsTest.java b/api/src/test/java/io/opencensus/internal/UtilsTest.java
new file mode 100644
index 00000000..2416eeb8
--- /dev/null
+++ b/api/src/test/java/io/opencensus/internal/UtilsTest.java
@@ -0,0 +1,88 @@
+/*
+ * 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.internal;
+
+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 Utils}. */
+@RunWith(JUnit4.class)
+public final class UtilsTest {
+  private static final String TEST_MESSAGE = "test message";
+
+  @Rule public ExpectedException thrown = ExpectedException.none();
+
+  @Test
+  public void checkArgument() {
+    Utils.checkArgument(true, TEST_MESSAGE);
+    thrown.expect(IllegalArgumentException.class);
+    thrown.expectMessage(TEST_MESSAGE);
+    Utils.checkArgument(false, TEST_MESSAGE);
+  }
+
+  @Test
+  public void checkState() {
+    Utils.checkNotNull(true, TEST_MESSAGE);
+    thrown.expect(IllegalStateException.class);
+    thrown.expectMessage(TEST_MESSAGE);
+    Utils.checkState(false, TEST_MESSAGE);
+  }
+
+  @Test
+  public void checkNotNull() {
+    Utils.checkNotNull(new Object(), TEST_MESSAGE);
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage(TEST_MESSAGE);
+    Utils.checkNotNull(null, TEST_MESSAGE);
+  }
+
+  @Test
+  public void checkIndex_Valid() {
+    Utils.checkIndex(1, 2);
+  }
+
+  @Test
+  public void checkIndex_NegativeSize() {
+    thrown.expect(IllegalArgumentException.class);
+    thrown.expectMessage("Negative size: -1");
+    Utils.checkIndex(0, -1);
+  }
+
+  @Test
+  public void checkIndex_NegativeIndex() {
+    thrown.expect(IndexOutOfBoundsException.class);
+    thrown.expectMessage("Index out of bounds: size=10, index=-2");
+    Utils.checkIndex(-2, 10);
+  }
+
+  @Test
+  public void checkIndex_IndexEqualToSize() {
+    thrown.expect(IndexOutOfBoundsException.class);
+    thrown.expectMessage("Index out of bounds: size=5, index=5");
+    Utils.checkIndex(5, 5);
+  }
+
+  @Test
+  public void checkIndex_IndexGreaterThanSize() {
+    thrown.expect(IndexOutOfBoundsException.class);
+    thrown.expectMessage("Index out of bounds: size=10, index=11");
+    Utils.checkIndex(11, 10);
+  }
+}