Only output on failing tests

src/testing-utils.ts

@@ -1,27 +1,37 @@
 import {TestInterface} from 'ava';
 
+type TestContext = {stdoutWrite: any, stderrWrite: any, testOutput: string};
+
+function wrapOutput(context: TestContext) {
+  return (str: any): boolean => {
+    if (typeof str === 'string') {
+      context.testOutput += str;
+    }
+    return true;
+  }
+}
+
 export function silenceDebugOutput(test: TestInterface<any>) {
-  const typedTest = test as TestInterface<{write: any}>;
+  const typedTest = test as TestInterface<TestContext>;
 
   typedTest.beforeEach(t => {
+      t.context.testOutput = "";
+
       const processStdoutWrite = process.stdout.write.bind(process.stdout);
-      t.context.write = processStdoutWrite;
-      process.stdout.write = (str: Uint8Array | string, encoding?: any, cb?: (err?: Error) => void) => {
-          // Core library will directly call process.stdout.write for commands
-          // We don't want debug output to be included in tests
-          if (typeof str === "string") {
-            str = str.replace(/::(info|debug|warning).*/, '');
-            if (str.trim() !== "") {
-                processStdoutWrite(str, encoding, cb);
-            }
-          } else {
-            processStdoutWrite(str, encoding, cb);
-          }
-          return true;
-      };
+      t.context.stdoutWrite = processStdoutWrite;
+      process.stdout.write = wrapOutput(t.context);
+
+      const processStderrWrite = process.stderr.write.bind(process.stderr);
+      t.context.stderrWrite = processStderrWrite;
+      process.stderr.write = wrapOutput(t.context);
   });
 
-  typedTest.afterEach(t => {
-      process.stdout.write = t.context.write;
+  typedTest.afterEach.always(t => {
+      process.stdout.write = t.context.stdoutWrite;
+      process.stderr.write = t.context.stderrWrite;
+
+      if (!t.passed) {
+        process.stdout.write(t.context.testOutput);
+      }
   });
 }