Convert the method parameter to lowercase

test/specs/requests.spec.js

@@ -17,6 +17,22 @@ describe('requests', function () {
     });
   });
 
+  it('should treat method value as lowercase string', function (done) {
+    axios({
+      url: '/foo',
+      method: 'POST'
+    }).then(function (response) {
+      expect(response.config.method).toBe('post');
+      done();
+    });
+
+    getAjaxRequest().then(function (request) {
+      request.respondWith({
+        status: 200
+      });
+    });
+  });
+
   it('should allow string arg as url, and config arg', function (done) {
     axios.post('/foo');