fix($httpBackend mock): getResponseHeader should be case insensitive

src/angular-mocks.js

@@ -766,7 +766,19 @@ function MockXhr() {
   };
 
   this.getResponseHeader = function(name) {
-    return this.$$headers[name];
+    // the lookup must be case insensitive, that's why we try two quick lookups and full scan at last
+    var header = this.$$headers[name];
+    if (header) return header;
+
+    name = angular.lowercase(name);
+    header = this.$$headers[name];
+    if (header) return header;
+
+    header = undefined;
+    angular.forEach(this.$$headers, function(headerVal, headerName) {
+      if (!header && angular.lowercase(headerName) == name) header = headerVal;
+    });
+    return header;
   };
 
   this.getAllResponseHeaders = function() {

test/angular-mocksSpec.js

@@ -470,6 +470,30 @@ describe('mocks', function() {
     });
 
 
+    it('should normalize when header name case when accessed via getResponseHeader', function() {
+      hb.when('GET', '/u1').respond(200, null, {'X-Fake': 'Header',
+                                                'Content-Type': 'application/json',
+                                                'Location': '/foo'});
+      var xhr = hb('GET', '/u1', null, noop, {});
+      hb.flush();
+      expect(xhr.getResponseHeader('x-fAKE')).toBe('Header');
+      expect(xhr.getResponseHeader('content-type')).toBe('application/json');
+      expect(xhr.getResponseHeader('Location')).toBe('/foo');
+    });
+
+
+    it('should normalize expect header name case when accessed via getResponseHeader', function() {
+      hb.expect('GET', '/u1').respond(200, null, {'X-Fake': 'Header',
+                                                'Content-Type': 'application/json',
+                                                'Location': '/foo'});
+      var xhr = hb('GET', '/u1', null, noop, {});
+      hb.flush();
+      expect(xhr.getResponseHeader('x-fAKE')).toBe('Header');
+      expect(xhr.getResponseHeader('content-type')).toBe('application/json');
+      expect(xhr.getResponseHeader('Location')).toBe('/foo');
+    });
+
+
     it('should preserve the order of requests', function() {
       hb.when('GET', '/url1').respond(200, 'first');
       hb.when('GET', '/url2').respond(201, 'second');