Summary Span: Add encoder/decoder for Server Stats. (#1272)

* Summary Span: Add encoder/decoder for Server Stats.

* Fixed build errors reported by Kokoro/Travis.

* Fixed review comments.
- Added missing javadoc annotation.
- included version in encoder/decoder.
- renamed get methods for ServerStats.

* Change version from 0.15 to 0.16
- also fixed CURRENT_VERSION for encoder/decoder and added test for it.

* Make ServerStatsEncoding public.

* Add Test ServerStatsFieldEnum.Size
replace traceOption() wiht getTraceOption()

3 files changed, 289 insertions, 0 deletions

diff --git a/api/src/test/java/io/opencensus/common/ServerStatsEncodingTest.java b/api/src/test/java/io/opencensus/common/ServerStatsEncodingTest.java
new file mode 100644
index 00000000..6db14a79
--- /dev/null
+++ b/api/src/test/java/io/opencensus/common/ServerStatsEncodingTest.java
@@ -0,0 +1,155 @@
+/*
+ * 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.common;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Unit tests for {@link ServerStatsEncoding}. */
+@RunWith(JUnit4.class)
+public class ServerStatsEncodingTest {
+
+  @Rule public final ExpectedException thrown = ExpectedException.none();
+
+  @Test
+  public void encodeDecodeTest() throws ServerStatsDeserializationException {
+    ServerStats serverStatsToBeEncoded = null;
+    ServerStats serverStatsDecoded = null;
+    byte[] serialized = null;
+
+    serverStatsToBeEncoded = ServerStats.create(31, 22, (byte) 1);
+    serialized = ServerStatsEncoding.toBytes(serverStatsToBeEncoded);
+    serverStatsDecoded = ServerStatsEncoding.parseBytes(serialized);
+    assertThat(serverStatsDecoded).isEqualTo(serverStatsToBeEncoded);
+
+    serverStatsToBeEncoded = ServerStats.create(0, 22, (byte) 0);
+    serialized = ServerStatsEncoding.toBytes(serverStatsToBeEncoded);
+    serverStatsDecoded = ServerStatsEncoding.parseBytes(serialized);
+    assertThat(serverStatsDecoded).isEqualTo(serverStatsToBeEncoded);
+
+    serverStatsToBeEncoded = ServerStats.create(450, 0, (byte) 0);
+    serialized = ServerStatsEncoding.toBytes(serverStatsToBeEncoded);
+    serverStatsDecoded = ServerStatsEncoding.parseBytes(serialized);
+    assertThat(serverStatsDecoded).isEqualTo(serverStatsToBeEncoded);
+  }
+
+  @Test
+  public void skipUnknownFieldTest() throws ServerStatsDeserializationException {
+    ServerStats serverStatsToBeEncoded = null;
+    ServerStats serverStatsDecoded = null;
+    byte[] serialized = null;
+
+    serverStatsToBeEncoded = ServerStats.create(31, 22, (byte) 1);
+    serialized = ServerStatsEncoding.toBytes(serverStatsToBeEncoded);
+
+    // Add new field at the end.
+    byte[] serializedExpanded = new byte[serialized.length + 9];
+    System.arraycopy(serialized, 0, serializedExpanded, 0, serialized.length);
+    final ByteBuffer bb = ByteBuffer.wrap(serializedExpanded);
+    bb.order(ByteOrder.LITTLE_ENDIAN);
+    bb.position(serialized.length);
+    bb.put((byte) 255);
+    bb.putLong(0L);
+    byte[] newSerialized = bb.array();
+
+    serverStatsDecoded = ServerStatsEncoding.parseBytes(newSerialized);
+    assertThat(serverStatsDecoded).isEqualTo(serverStatsToBeEncoded);
+  }
+
+  @Test
+  public void negativeLbLatencyValueTest() throws ServerStatsDeserializationException {
+    ServerStats serverStatsToBeEncoded = null;
+    ServerStats serverStatsDecoded = null;
+    byte[] serialized = null;
+
+    serverStatsToBeEncoded = ServerStats.create(31, 22, (byte) 1);
+    serialized = ServerStatsEncoding.toBytes(serverStatsToBeEncoded);
+
+    // update serialized byte[] with negative value for lbLatency.
+    final ByteBuffer bb = ByteBuffer.wrap(serialized);
+    bb.order(ByteOrder.LITTLE_ENDIAN);
+    bb.position(2);
+    bb.putLong(-100L);
+
+    byte[] newSerialized = bb.array();
+    thrown.expect(ServerStatsDeserializationException.class);
+    thrown.expectMessage("Serialized ServiceStats contains invalid values");
+    ServerStatsEncoding.parseBytes(newSerialized);
+  }
+
+  @Test
+  public void negativeServerLatencyValueTest() throws ServerStatsDeserializationException {
+    ServerStats serverStatsToBeEncoded = null;
+    ServerStats serverStatsDecoded = null;
+    byte[] serialized = null;
+
+    serverStatsToBeEncoded = ServerStats.create(31, 22, (byte) 1);
+    serialized = ServerStatsEncoding.toBytes(serverStatsToBeEncoded);
+
+    // update serialized byte[] with negative value for serviceLatency.
+    final ByteBuffer bb = ByteBuffer.wrap(serialized);
+    bb.order(ByteOrder.LITTLE_ENDIAN);
+    bb.position(11);
+    bb.putLong(-101L);
+
+    byte[] newSerialized = bb.array();
+    thrown.expect(ServerStatsDeserializationException.class);
+    thrown.expectMessage("Serialized ServiceStats contains invalid values");
+    ServerStatsEncoding.parseBytes(newSerialized);
+  }
+
+  @Test
+  public void emptySerializedBuffer() throws ServerStatsDeserializationException {
+    final ByteBuffer bb = ByteBuffer.allocate(0);
+    bb.order(ByteOrder.LITTLE_ENDIAN);
+
+    byte[] newSerialized = bb.array();
+    thrown.expect(ServerStatsDeserializationException.class);
+    thrown.expectMessage("Serialized ServerStats buffer is empty");
+    ServerStatsEncoding.parseBytes(newSerialized);
+  }
+
+  @Test
+  public void invalidNegativeVersion() throws ServerStatsDeserializationException {
+    final ByteBuffer bb = ByteBuffer.allocate(10);
+    bb.order(ByteOrder.LITTLE_ENDIAN);
+    bb.put((byte) -1);
+    byte[] newSerialized = bb.array();
+    thrown.expect(ServerStatsDeserializationException.class);
+    thrown.expectMessage("Invalid ServerStats version: -1");
+    ServerStatsEncoding.parseBytes(newSerialized);
+  }
+
+  @Test
+  public void invalidCompatibleVersion() throws ServerStatsDeserializationException {
+    final ByteBuffer bb = ByteBuffer.allocate(10);
+    bb.order(ByteOrder.LITTLE_ENDIAN);
+    bb.put((byte) (ServerStatsEncoding.CURRENT_VERSION + 1));
+    byte[] newSerialized = bb.array();
+    thrown.expect(ServerStatsDeserializationException.class);
+    thrown.expectMessage(
+        "Invalid ServerStats version: " + (ServerStatsEncoding.CURRENT_VERSION + 1));
+    ServerStatsEncoding.parseBytes(newSerialized);
+  }
+}
diff --git a/api/src/test/java/io/opencensus/common/ServerStatsFieldEnumsTest.java b/api/src/test/java/io/opencensus/common/ServerStatsFieldEnumsTest.java
new file mode 100644
index 00000000..ed786f6c
--- /dev/null
+++ b/api/src/test/java/io/opencensus/common/ServerStatsFieldEnumsTest.java
@@ -0,0 +1,56 @@
+/*
+ * 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.common;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import io.opencensus.common.ServerStatsFieldEnums.Id;
+import io.opencensus.common.ServerStatsFieldEnums.Size;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Unit tests for {@link ServerStatsFieldEnums}. */
+@RunWith(JUnit4.class)
+public class ServerStatsFieldEnumsTest {
+
+  @Test
+  public void enumIdValueOfTest() {
+    assertThat(Id.valueOf(0)).isEqualTo(Id.SERVER_STATS_LB_LATENCY_ID);
+    assertThat(Id.valueOf(1)).isEqualTo(Id.SERVER_STATS_SERVICE_LATENCY_ID);
+    assertThat(Id.valueOf(2)).isEqualTo(Id.SERVER_STATS_TRACE_OPTION_ID);
+  }
+
+  @Test
+  public void enumIdInvalidValueOfTest() {
+    assertThat(Id.valueOf(-1)).isNull();
+    assertThat(Id.valueOf(Id.values().length)).isNull();
+    assertThat(Id.valueOf(Id.values().length + 1)).isNull();
+  }
+
+  @Test
+  public void enumSizeValueTest() {
+    assertThat(Size.SERVER_STATS_LB_LATENCY_SIZE.value()).isEqualTo(8);
+    assertThat(Size.SERVER_STATS_SERVICE_LATENCY_SIZE.value()).isEqualTo(8);
+    assertThat(Size.SERVER_STATS_TRACE_OPTION_SIZE.value()).isEqualTo(1);
+  }
+
+  @Test
+  public void totalSizeTest() {
+    assertThat(ServerStatsFieldEnums.getTotalSize()).isEqualTo(20);
+  }
+}
diff --git a/api/src/test/java/io/opencensus/common/ServerStatsTest.java b/api/src/test/java/io/opencensus/common/ServerStatsTest.java
new file mode 100644
index 00000000..620bbb4f
--- /dev/null
+++ b/api/src/test/java/io/opencensus/common/ServerStatsTest.java
@@ -0,0 +1,78 @@
+/*
+ * 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.common;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Unit tests for {@link ServerStats}. */
+@RunWith(JUnit4.class)
+public class ServerStatsTest {
+
+  @Rule public ExpectedException thrown = ExpectedException.none();
+
+  @Test
+  public void serverStatsCreate() {
+    ServerStats serverStats = null;
+
+    serverStats = ServerStats.create(31, 22, (byte) 0);
+    assertThat(serverStats.getLbLatencyNs()).isEqualTo(31);
+    assertThat(serverStats.getServiceLatencyNs()).isEqualTo(22);
+    assertThat(serverStats.getTraceOption()).isEqualTo((byte) 0);
+
+    serverStats = ServerStats.create(1000011L, 900022L, (byte) 1);
+    assertThat(serverStats.getLbLatencyNs()).isEqualTo(1000011L);
+    assertThat(serverStats.getServiceLatencyNs()).isEqualTo(900022L);
+    assertThat(serverStats.getTraceOption()).isEqualTo((byte) 1);
+
+    serverStats = ServerStats.create(0, 22, (byte) 0);
+    assertThat(serverStats.getLbLatencyNs()).isEqualTo(0);
+    assertThat(serverStats.getServiceLatencyNs()).isEqualTo(22);
+    assertThat(serverStats.getTraceOption()).isEqualTo((byte) 0);
+
+    serverStats = ServerStats.create(1010, 0, (byte) 0);
+    assertThat(serverStats.getLbLatencyNs()).isEqualTo(1010);
+    assertThat(serverStats.getServiceLatencyNs()).isEqualTo(0);
+    assertThat(serverStats.getTraceOption()).isEqualTo((byte) 0);
+  }
+
+  @Test
+  public void create_LbLatencyNegative() {
+    thrown.expect(IllegalArgumentException.class);
+    thrown.expectMessage("'getLbLatencyNs' is less than zero");
+    ServerStats.create(-1L, 100, (byte) 0);
+  }
+
+  @Test
+  public void create_ServerLatencyNegative() {
+    thrown.expect(IllegalArgumentException.class);
+    thrown.expectMessage("'getServiceLatencyNs' is less than zero");
+    ServerStats.create(100L, -1L, (byte) 0);
+  }
+
+  @Test
+  public void create_LbLatencyAndServerLatencyNegative() {
+    thrown.expect(IllegalArgumentException.class);
+    thrown.expectMessage("'getLbLatencyNs' is less than zero");
+    ServerStats.create(-100L, -1L, (byte) 0);
+  }
+}