From cffe99f0bb2fd9ab4eaa9b4c2ca7a57aa7211a57 Mon Sep 17 00:00:00 2001
From: vadimt <vadimt@google.com>
Date: Fri, 17 Jan 2020 12:20:20 -0800
Subject: [PATCH] Automatically diagnosing known flakes

It often takes a long time to fix a flake; meanwhile it takes a lot of
time for sheriffs to identify whether to register a new flake for a
failure.

This CL adds automatic identifies identification of one know flake type.
Once identified, it rewrites the error so that:
1. Flakes clustering tool that has only rudimentary clustering, places
all flakes of this kind in the same cluster (not multiple ones like
now). This is a step towards using clustering tool for monitoring
flakes;
2. Sheriff immediately sees that the issue is known.

Change-Id: I86a0762665cb21434289e1be00b60bd76fec4142
---
 .../util/rule/FailureInvestigator.java        | 54 +++++++++++++++++++
 .../launcher3/util/rule/FailureWatcher.java   | 27 ++++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 tests/src/com/android/launcher3/util/rule/FailureInvestigator.java

diff --git a/tests/src/com/android/launcher3/util/rule/FailureInvestigator.java b/tests/src/com/android/launcher3/util/rule/FailureInvestigator.java
new file mode 100644
index 0000000000..56c885d85b
--- /dev/null
+++ b/tests/src/com/android/launcher3/util/rule/FailureInvestigator.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * 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.android.launcher3.util.rule;
+
+import static androidx.test.InstrumentationRegistry.getInstrumentation;
+
+import androidx.test.uiautomator.UiDevice;
+
+import java.io.IOException;
+import java.util.regex.Pattern;
+
+class FailureInvestigator {
+    private static boolean matches(String regex, CharSequence string) {
+        return Pattern.compile(regex).matcher(string).find();
+    }
+
+    static int getBugForFailure(CharSequence exception, String testsStartTime) {
+        final String logSinceTestsStart;
+        try {
+            logSinceTestsStart =
+                    UiDevice.getInstance(getInstrumentation())
+                            .executeShellCommand("logcat -d -t " + testsStartTime.replace(" ", ""));
+        } catch (IOException e) {
+            return 0;
+        }
+
+        if (matches(
+                "java.lang.AssertionError: http://go/tapl : Tests are broken by a non-Launcher "
+                        + "system error: Phone is locked",
+                exception)) {
+            if (matches(
+                    "BroadcastQueue: Can't deliver broadcast to com.android.systemui.*Crashing it",
+                    logSinceTestsStart)) {
+                return 147845913;
+            }
+        }
+
+        return 0;
+    }
+}
diff --git a/tests/src/com/android/launcher3/util/rule/FailureWatcher.java b/tests/src/com/android/launcher3/util/rule/FailureWatcher.java
index cdda0f0dcc..feb89b925f 100644
--- a/tests/src/com/android/launcher3/util/rule/FailureWatcher.java
+++ b/tests/src/com/android/launcher3/util/rule/FailureWatcher.java
@@ -8,10 +8,13 @@ import androidx.test.uiautomator.UiDevice;
 
 import org.junit.rules.TestWatcher;
 import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
 
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
 
 public class FailureWatcher extends TestWatcher {
     private static final String TAG = "FailureWatcher";
@@ -35,6 +38,30 @@ public class FailureWatcher extends TestWatcher {
         }
     }
 
+    private static final String testsStartTime =
+            new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(new Date());
+
+    @Override
+    public Statement apply(Statement base, Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                try {
+                    base.evaluate();
+                } catch (Throwable e) {
+                    final int bug =
+                            FailureInvestigator.getBugForFailure(e.toString(), testsStartTime);
+                    if (bug == 0) throw e;
+
+                    Log.e(TAG, "Known bug found for the original failure "
+                            + android.util.Log.getStackTraceString(e));
+                    throw new AssertionError(
+                            "Detected a failure that matches a known bug b/" + bug);
+                }
+            }
+        };
+    }
+
     @Override
     protected void failed(Throwable e, Description description) {
         onError(mDevice, description, e);