to yield output satisfying: Buffer up the chunks so that the assertio…

…n can run on the same subject multiple times.
unexpectedjs · Sep 23, 2015 · faaa094 · faaa094
1 parent 2e1d0c4
commit faaa094
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Showing 2 changed files with 25 additions and 9 deletions.
diff --git a/lib/unexpectedStream.js b/lib/unexpectedStream.js
@@ -47,13 +47,19 @@ module.exports = {
             var extraArgs = Array.prototype.slice.call(arguments, 2),
                 mustConcat = this.alternations[0] === 'output';
 
-            expect(subject, 'to have property', 'readable', true);
-
             return expect.promise(function (resolve, reject) {
-                var chunks = [];
-                subject.on('data', function (chunk) {
-                    chunks.push(chunk);
-                }).on('end', function () {
+                if (!subject._unexpectedStreamChunksPromise) {
+                    subject._unexpectedStreamChunksPromise = expect.promise(function (resolve, reject) {
+                        expect(subject, 'to have property', 'readable', true);
+                        var chunks = [];
+                        subject.on('data', function (chunk) {
+                            chunks.push(chunk);
+                        }).on('end', function () {
+                            resolve(chunks);
+                        }).on('error', reject);
+                    });
+                }
+                subject._unexpectedStreamChunksPromise.then(function (chunks) {
                     var result;
                     if (mustConcat) {
                         if (chunks.length > 0 && chunks.every(function (chunk) { return typeof chunk === 'string'; })) {
@@ -72,10 +78,10 @@ module.exports = {
                         result = chunks;
                     }
                     resolve(result);
-                }).on('error', reject);
+                });
             }).then(function (result) {
                 return expect.apply(expect, [result, 'to satisfy assertion'].concat(extraArgs));
             });
         });
     }
-};
+};
diff --git a/test/unexpectedStream.js b/test/unexpectedStream.js
@@ -11,7 +11,7 @@ describe('unexpected-stream', function () {
 
     expect.output.preferredWidth = 150;
 
-    describe('to yield output', function () {
+    describe('to yield output satisfying', function () {
         it('should buffer up the output of a readable stream that outputs buffers', function () {
             return expect(fs.createReadStream(fooTxtPath), 'to yield output satisfying', new Buffer('foobarquux\n', 'utf-8'));
         });
@@ -31,6 +31,16 @@ describe('unexpected-stream', function () {
                     "  +blah"
             );
         });
+
+        it('should be able to assert the output of the same stream multiple times', function () {
+            var readStream = fs.createReadStream(fooTxtPath, {encoding: 'utf-8'});
+            return expect.promise.all([
+                expect(readStream, 'to yield output satisfying', 'to equal', 'foobarquux\n'),
+                expect(readStream, 'to yield output satisfying', 'to equal', 'foobarquux\n')
+            ]).then(function () {
+                return expect(readStream, 'to yield output satisfying', 'to equal', 'foobarquux\n');
+            });
+        });
     });
 
     describe('to yield chunks', function () {