Preserving context binding, fixes #4

bahmutov · Sep 30, 2015 · 535f96c · 535f96c
1 parent 0e85b2a
commit 535f96c
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Showing 4 changed files with 48 additions and 5 deletions.
diff --git a/README.md b/README.md
@@ -154,6 +154,23 @@ describeIt(..., function (getFn) {
 });
 ```
 
+## Context is preserved
+
+We follow the convention and preserve the original context inside the `describeIt` callback, thus
+you can assign the extracted value to a property
+
+```js
+desribeFunction(fooFilename, 'getFoo()', function (getFn) {
+  beforeEach(function () {
+    this.getFoo = getFn();
+  });
+
+  it('returns "foo"', function () {
+    la(this.getFoo() === 'foo');
+  });
+});
+```
+
 [1]: http://philipwalton.com/articles/how-to-unit-test-private-functions-in-javascript/
 [2]: https://github.com/jasmine/jasmine/pull/908
 [3]: http://glebbahmutov.com/blog/picking-javascript-testing-framework/

diff --git a/describe-it.js b/describe-it.js
@@ -83,7 +83,7 @@ function describeIt(filename, functionSignature, useBeforeEach, cb) {
     }
 
     log('executing describeIt callback');
-    cb(returnsFn);
+    cb.call(this, returnsFn);
 
     afterFn(function () {
       log('deleting __exports object', global.__exports);

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "describe-it",
-  "version": "1.4.0",
+  "version": "1.5.0",
   "description": "Extracts a private function / variable for BDD unit testing",
   "main": "describe-it.js",
   "scripts": {

diff --git a/test/get-foo-spec.js b/test/get-foo-spec.js
@@ -1,6 +1,7 @@
 var desribeFunction = require('..');
+var fooFilename = __dirname + '/foo.js';
 
-desribeFunction(__dirname + '/foo.js', 'getFoo()', function (getFn) {
+desribeFunction(fooFilename, 'getFoo()', function (getFn) {
   it('has function argument', function () {
     la(typeof getFn === 'function');
   });
@@ -16,14 +17,14 @@ desribeFunction(__dirname + '/foo.js', 'getFoo()', function (getFn) {
   });
 });
 
-desribeFunction(__dirname + '/foo.js', 'getFoo()', function (getFn) {
+desribeFunction(fooFilename, 'getFoo()', function (getFn) {
   it('returns "foo"', function () {
     var getFoo = getFn();
     la(getFoo() === 'foo');
   });
 });
 
-desribeFunction(__dirname + '/foo.js', 'getFoo()', function (getFn) {
+desribeFunction(fooFilename, 'getFoo()', function (getFn) {
   var getFoo;
 
   beforeEach(function () {
@@ -38,3 +39,28 @@ desribeFunction(__dirname + '/foo.js', 'getFoo()', function (getFn) {
     la(getFn() === getFoo);
   });
 });
+
+// storing value in 'this'
+desribeFunction(fooFilename, 'getFoo()', function (getFn) {
+  beforeEach(function () {
+    this.getFoo = getFn();
+  });
+
+  it('returns "foo"', function () {
+    la(this.getFoo() === 'foo');
+  });
+});
+
+// using assign shortcut
+desribeFunction(fooFilename, 'getFoo()', function (getFn) {
+  function assign(property, get) {
+    this[property] = get();
+    return this[property];
+  }
+
+  beforeEach(assign.bind(this.ctx, 'getFoo', getFn));
+
+  it('returns "foo"', function () {
+    la(this.getFoo() === 'foo');
+  });
+});