fix bug in expect success code

would return errors if success code was returned

Makefile

@@ -15,8 +15,13 @@ coverage: build
 fmt:
 	go fmt $(PACKAGES)
 
+
 lint:
-	-golangci-lint run
+	# running golangci-lint run twice, ignoring the first run
+	# this is to workaround a bug in golangci-lint's type cache which can result
+	# in false type errors on the first run
+	# https://github.com/golangci/golangci-lint/issues/885
+	-golangci-lint run > /dev/null 2>&1
 	golangci-lint run
 
 vet:

middleware.go

@@ -123,20 +123,20 @@ type codeChecker struct {
 }
 
 func (c *codeChecker) checkCode(resp *http.Response, err error) (*http.Response, error) {
-	if err != nil || resp == nil {
-		return resp, err
+	switch {
+	case err != nil, resp == nil:
+	case c.code == expectSuccessCode:
+		if resp.StatusCode < 200 || resp.StatusCode > 299 {
+			err = merry.
+				Errorf("server returned an unsuccessful status code: %d", resp.StatusCode).
+				WithHTTPCode(resp.StatusCode)
+		}
+	case c.code != resp.StatusCode:
+		err = merry.
+			Errorf("server returned unexpected status code.  expected: %d, received: %d", c.code, resp.StatusCode).
+			WithHTTPCode(resp.StatusCode)
 	}
-	if c.code == expectSuccessCode && (resp.StatusCode < 200 || resp.StatusCode > 299) { // special case, expect a success code
-		err := merry.Errorf("server returned an unsuccessful status code: %d", resp.StatusCode)
-		err = err.WithHTTPCode(resp.StatusCode)
-		return resp, err
-	}
-	if c.code != resp.StatusCode {
-		err := merry.Errorf("server returned unexpected status code.  expected: %d, received: %d", c.code, resp.StatusCode)
-		err = err.WithHTTPCode(resp.StatusCode)
-		return resp, err
-	}
-	return resp, nil
+	return resp, err
 }
 
 func getCodeChecker(req *http.Request) (*http.Request, *codeChecker) {

middleware_test.go

@@ -167,9 +167,11 @@ func TestExpectCode(t *testing.T) {
 
 func TestExpectSuccessCode(t *testing.T) {
 
+	codeToReturn := 407
+	bodyToReturn := "boom!"
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.WriteHeader(407)
-		w.Write([]byte("boom!"))
+		w.WriteHeader(codeToReturn)
+		_, _ = w.Write([]byte(bodyToReturn))
 	}))
 	defer ts.Close()
 
@@ -187,6 +189,14 @@ func TestExpectSuccessCode(t *testing.T) {
 	require.Error(t, err)
 	assert.Contains(t, err.Error(), "code: 407")
 	assert.Equal(t, 407, merry.HTTPCode(err))
+
+	// test positive path: if success code is returned, then no error should be returned
+	successCodes := []int{200, 201, 204, 278}
+	for _, code := range successCodes {
+		codeToReturn = code
+		_, _, err := Receive(Get(ts.URL), ExpectSuccessCode())
+		require.NoError(t, err, "should not have received an error for code %v", code)
+	}
 }
 
 func ExampleMiddleware() {