Reduce excessive log.

The purpose of this cl is to reduce the output snippet.
This is most prevalent when tests fails on exit,
and executed in large batches.

Bug: 1086276
Change-Id: I73072f072e12597cdb5dfe53f6153ffaf9cf09d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2226089Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Ilia Samsonov <isamsonov@google.com>
Cr-Commit-Position: refs/heads/master@{#774224}

base/test/launcher/test_launcher.cc

@@ -1858,11 +1858,17 @@ std::string GetTestOutputSnippet(const TestResult& result,
                                     run_pos);
   // Only clip the snippet to the "OK" message if the test really
   // succeeded. It still might have e.g. crashed after printing it.
-  if (end_pos == std::string::npos &&
-      result.status == TestResult::TEST_SUCCESS) {
-    end_pos = full_output.find(std::string("[       OK ] ") +
-                               result.full_name,
-                               run_pos);
+  if (end_pos == std::string::npos) {
+    if (result.status == TestResult::TEST_SUCCESS) {
+      end_pos = full_output.find(std::string("[       OK ] ") +
+                                result.full_name,
+                                run_pos);
+    } else {
+      // If test is not successful, include all output until subsequent test.
+      end_pos = full_output.find(std::string("[ RUN      ]"), run_pos + 1);
+      if (end_pos != std::string::npos)
+        end_pos--;
+    }
   }
   if (end_pos != std::string::npos) {
     size_t newline_pos = full_output.find("\n", end_pos);

base/test/launcher/test_launcher_unittest.cc

@@ -764,6 +764,40 @@ TEST_F(UnitTestLauncherDelegateTester, RunMockTests) {
       iteration_val, "MockUnitTests.NoRunTest", "NOTRUN", 0u));
 }
 
+// Validate GetTestOutputSnippetTest assigns correct output snippet.
+TEST(TestLauncherTools, GetTestOutputSnippetTest) {
+  const std::string output =
+      "[ RUN      ] TestCase.FirstTest\n"
+      "[       OK ] TestCase.FirstTest (0 ms)\n"
+      "Post first test output\n"
+      "[ RUN      ] TestCase.SecondTest\n"
+      "[  FAILED  ] TestCase.SecondTest (0 ms)\n"
+      "Post second test output";
+  TestResult result;
+
+  // test snippet of a successful test
+  result.full_name = "TestCase.FirstTest";
+  result.status = TestResult::TEST_SUCCESS;
+  EXPECT_EQ(GetTestOutputSnippet(result, output),
+            "[ RUN      ] TestCase.FirstTest\n"
+            "[       OK ] TestCase.FirstTest (0 ms)\n");
+
+  // test snippet of a failure on exit tests should include output
+  // after test concluded, but not subsequent tests output.
+  result.status = TestResult::TEST_FAILURE_ON_EXIT;
+  EXPECT_EQ(GetTestOutputSnippet(result, output),
+            "[ RUN      ] TestCase.FirstTest\n"
+            "[       OK ] TestCase.FirstTest (0 ms)\n"
+            "Post first test output\n");
+
+  // test snippet of a failed test
+  result.full_name = "TestCase.SecondTest";
+  result.status = TestResult::TEST_FAILURE;
+  EXPECT_EQ(GetTestOutputSnippet(result, output),
+            "[ RUN      ] TestCase.SecondTest\n"
+            "[  FAILED  ] TestCase.SecondTest (0 ms)\n");
+}
+
 }  // namespace
 
 }  // namespace base