Merge b76c817 into 4aa2cb9

lib/run-context.js

@@ -12,6 +12,21 @@ var EventEmitter = require('events').EventEmitter;
 var helpers = require('./');
 var TestAdapter = require('./adapter').TestAdapter;
 
+/**
+ * Wrap callback so it can't get called twice
+ */
+const callbackWrapper = done => {
+  let callbackHandled = false;
+  const callback = err => {
+    if (!callbackHandled) {
+      callbackHandled = true;
+      done(err);
+    }
+  };
+
+  return callback;
+};
+
 /**
  * This class provide a run context object to façade the complexity involved in setting
  * up a generator for testing
@@ -108,14 +123,15 @@ RunContext.prototype._run = function() {
     helpers.mockLocalConfig(this.generator, this.localConfig);
   }
 
-  this.generator.on(
-    'error',
+  const callback = callbackWrapper(
     function(err) {
       if (!this.emit('error', err)) {
         throw err;
       }
     }.bind(this)
   );
+
+  this.generator.on('error', callback);
   this.generator.once(
     'end',
     function() {
@@ -129,7 +145,7 @@ RunContext.prototype._run = function() {
 
   const generatorPromise = this.generator.run();
   if (!this.settings.compatibility) {
-    generatorPromise.catch(err => this.emit('error', err));
+    generatorPromise.catch(callback);
   }
 };
 

test/helpers.js

@@ -181,5 +181,57 @@ describe('yeoman-test', function() {
       var runContext = helpers.run(helpers.createDummyGenerator(), { foo: 1 });
       assert.equal(runContext.settings.foo, 1);
     });
+
+    it('catch env errors', function(done) {
+      helpers
+        .run(
+          class extends helpers.createDummyGenerator() {
+            throws() {
+              this.env.emit('error', new Error());
+            }
+          }
+        )
+        .on('error', _ => {
+          done();
+        });
+    });
+
+    it('catch generator emitted errors', function(done) {
+      helpers
+        .run(
+          class extends helpers.createDummyGenerator() {
+            throws() {
+              this.emit('error', new Error());
+            }
+          }
+        )
+        .on('error', _ => {
+          done();
+        });
+    });
+
+    it('catch generator thrown errors', function(done) {
+      helpers
+        .run(
+          class extends helpers.createDummyGenerator() {
+            throws() {
+              throw new Error();
+            }
+          }
+        )
+        .on('error', _ => {
+          done();
+        });
+    });
+
+    // This is a workaround for corner case were an error is not correctly emitted
+    // See https://github.com/yeoman/generator/pull/1155
+    it('catch run errors', function(done) {
+      helpers
+        .run(class extends Generator {}, { catchGeneratorError: true })
+        .on('error', _ => {
+          done();
+        });
+    });
   });
 });