Implement LcovMerger.

LcovMerger is a tool that merges all the intermediate lcov tracefiles (with .dat extension) found under a coverage directory and prints the merged tracefile to a given output file.

A custom implementation for merging lcov tracefiles is needed because the merging functionality of lcov itself is very slow.

LcovMerger is required to get a single coverage report (lcov tracefile) from a bazel coverage command that executes multiple tests.

ATM LcovMerger is only invoked by tools/test/collect_coverage.sh that collects and merges the tracefiles from a single test invocation. It will also be used from a CoverageReportAction.

Progress on #5246.

PiperOrigin-RevId: 200054506

1 files changed, 81 insertions, 0 deletions

diff --git a/tools/test/LcovMerger/javatests/com/google/devtools/lcovmerger/CoverageTest.java b/tools/test/LcovMerger/javatests/com/google/devtools/lcovmerger/CoverageTest.java
new file mode 100644
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+++ b/tools/test/LcovMerger/javatests/com/google/devtools/lcovmerger/CoverageTest.java
@@ -0,0 +1,81 @@
+// Copyright 2016 The Bazel Authors. All rights reserved.
+//
+// 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 com.google.devtools.lcovmerger;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.devtools.lcovmerger.LcovMergerTestUtils.assertMergedSourceFile;
+import static com.google.devtools.lcovmerger.LcovMergerTestUtils.assertTracefile1;
+import static com.google.devtools.lcovmerger.LcovMergerTestUtils.createLinesExecution1;
+import static com.google.devtools.lcovmerger.LcovMergerTestUtils.createLinesExecution2;
+import static com.google.devtools.lcovmerger.LcovMergerTestUtils.createSourceFile1;
+import static com.google.devtools.lcovmerger.LcovMergerTestUtils.createSourceFile2;
+
+import com.google.common.collect.Iterables;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/**
+ * Test for LcovMerger.
+ */
+@RunWith(JUnit4.class)
+public class CoverageTest {
+
+  private Coverage coverage;
+
+  @Before
+  public void initializeCoverage() {
+    coverage = new Coverage();
+  }
+
+  @Test
+  public void testOneTracefile() {
+    SourceFileCoverage sourceFileCoverage =
+        createSourceFile1(createLinesExecution1());
+    coverage.add(sourceFileCoverage);
+    assertThat(coverage.getAllSourceFiles()).hasSize(1);
+    assertTracefile1(Iterables.get(coverage.getAllSourceFiles(), 0));
+  }
+
+  @Test
+  public void testTwoOverlappingTracefiles() {
+    int[] linesExecution1 = createLinesExecution1();
+    int[] linesExecution2 = createLinesExecution2();
+    SourceFileCoverage sourceFileCoverage1 = createSourceFile1(linesExecution1);
+    SourceFileCoverage sourceFileCoverage2 = createSourceFile2(linesExecution2);
+
+    coverage.add(sourceFileCoverage1);
+    coverage.add(sourceFileCoverage2);
+
+    assertThat(coverage.getAllSourceFiles()).hasSize(1);
+    SourceFileCoverage merged = Iterables.get(coverage.getAllSourceFiles(), 0);
+    assertMergedSourceFile(merged, linesExecution1, linesExecution2);
+  }
+
+  @Test
+  public void testTwoTracefiles() {
+    SourceFileCoverage sourceFileCoverage1 =
+        createSourceFile1(createLinesExecution1());
+    SourceFileCoverage sourceFileCoverage2 = createSourceFile1(
+        "SOME_OTHER_FILENAME", createLinesExecution1());
+
+    coverage.add(sourceFileCoverage1);
+    coverage.add(sourceFileCoverage2);
+    assertThat(coverage.getAllSourceFiles()).hasSize(2);
+    assertTracefile1(Iterables.get(coverage.getAllSourceFiles(), 0));
+    assertTracefile1(Iterables.get(coverage.getAllSourceFiles(), 1));
+  }
+}