Merge remote-tracking branch 'origin/master' into ej/sourceMapSupport…

…Redirect

test.js

@@ -1,7 +1,5 @@
-const underTest = require('./source-map-support');
-underTest.install({
-  emptyCacheBetweenOperations: true // Needed to be able to test for failure
-});
+// Note: some tests rely on side-effects from prior tests.
+// You may not get meaningful results running a subset of tests.
 
 const priorErrorPrepareStackTrace = Error.prepareStackTrace;
 const priorProcessEmit = process.emit;
@@ -737,4 +735,75 @@ describe('redirects require() of "source-map-support" to this module', function(
       assert.strictEqual(redirectedRequest, require.resolve('.'));
     }
   });
-});
+});
+
+describe('uninstall', function() {
+  this.beforeEach(function() {
+    underTest.uninstall();
+    process.emit = priorProcessEmit;
+    Error.prepareStackTrace = priorErrorPrepareStackTrace;
+  });
+
+  it('uninstall removes hooks and source-mapping behavior', function() {
+    assert.strictEqual(Error.prepareStackTrace, priorErrorPrepareStackTrace);
+    assert.strictEqual(process.emit, priorProcessEmit);
+    normalThrowWithoutSourceMapSupportInstalled();
+  });
+
+  it('install re-adds hooks', function() {
+    installSms();
+    normalThrow();
+  });
+
+  it('uninstall removes prepareStackTrace even in presence of third-party hooks if none were installed before us', function() {
+    installSms();
+    const wrappedPrepareStackTrace = Error.prepareStackTrace;
+    let pstInvocations = 0;
+    function thirdPartyPrepareStackTraceHook() {
+      pstInvocations++;
+      return wrappedPrepareStackTrace.apply(this, arguments);
+    }
+    Error.prepareStackTrace = thirdPartyPrepareStackTraceHook;
+    underTest.uninstall();
+    assert.strictEqual(Error.prepareStackTrace, undefined);
+    assert(pstInvocations === 0);
+  });
+
+  it('uninstall preserves third-party prepareStackTrace hooks if one was installed before us', function() {
+    let beforeInvocations = 0;
+    function thirdPartyPrepareStackTraceHookInstalledBefore() {
+      beforeInvocations++;
+      return 'foo';
+    }
+    Error.prepareStackTrace = thirdPartyPrepareStackTraceHookInstalledBefore;
+    installSms();
+    const wrappedPrepareStackTrace = Error.prepareStackTrace;
+    let afterInvocations = 0;
+    function thirdPartyPrepareStackTraceHookInstalledAfter() {
+      afterInvocations++;
+      return wrappedPrepareStackTrace.apply(this, arguments);
+    }
+    Error.prepareStackTrace = thirdPartyPrepareStackTraceHookInstalledAfter;
+    underTest.uninstall();
+    assert.strictEqual(Error.prepareStackTrace, thirdPartyPrepareStackTraceHookInstalledAfter);
+    assert.strictEqual(new Error().stack, 'foo');
+    assert.strictEqual(beforeInvocations, 1);
+    assert.strictEqual(afterInvocations, 1);
+  });
+
+  it('uninstall preserves third-party process.emit hooks installed after us', function() {
+    installSms();
+    const wrappedProcessEmit = process.emit;
+    let peInvocations = 0;
+    function thirdPartyProcessEmit() {
+      peInvocations++;
+      return wrappedProcessEmit.apply(this, arguments);
+    }
+    process.emit = thirdPartyProcessEmit;
+    underTest.uninstall();
+    assert.strictEqual(process.emit, thirdPartyProcessEmit);
+    normalThrowWithoutSourceMapSupportInstalled();
+    process.emit('foo');
+    assert(peInvocations >= 1);
+  });
+});