Added linter specific testdata file

test/testdata/responsewriterlint.go

@@ -0,0 +1,66 @@
+//golangcitest:args -Eresponsewriterlint
+package testdata
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+)
+
+type notAResponseWriter struct{}
+
+func (narw notAResponseWriter) Write(in []byte) (int, error) {
+	// actually do nothing
+	return 42, errors.New("no")
+}
+
+func (narw notAResponseWriter) WriteHeader(code int) {
+	// also do nothing
+}
+
+func (narw notAResponseWriter) Header() http.Header {
+	return http.Header{}
+}
+
+type rwlRandom struct{}
+
+func rwlExampleOne(w http.ResponseWriter, r *http.Request) {
+	w.Header().Add("some header", "value")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write([]byte(`boys in the yard`))
+}
+
+func rwlExampleTwo(s string, r *http.Request) error {
+	fmt.Printf("this is a thing")
+
+	return nil
+}
+
+func rwlFakeWriter(w notAResponseWriter) {
+	w.Header().Add("something", "other")
+	w.WriteHeader(420)
+	_, _ = w.Write([]byte(`fooled ya`))
+}
+
+func (b rwlRandom) method(w http.ResponseWriter, r *http.Request) {
+	w.Header().Add("some header", "value")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write([]byte(`boys in the yard`))
+}
+
+func (b *rwlRandom) methodPointer(w http.ResponseWriter, r *http.Request) {
+	w.Header().Add("some header", "value")
+	_, _ = w.Write([]byte(`boys in the yard`))
+	w.WriteHeader(http.StatusOK) // want "function methodPointer: http.ResponseWriter.Write is called before http.ResponseWriter.WriteHeader. Headers are already sent, this has no effect."
+}
+
+func rwlExampleThree(bloe http.ResponseWriter, r *http.Request) {
+	_, _ = bloe.Write([]byte(`hellyea`)) // want "function rwlExampleThree: Multiple calls to http.ResponseWriter.Write in the same function body. This is most probably a bug."
+
+	bloe.WriteHeader(http.StatusBadRequest)          // want "function rwlExampleThree: Multiple calls to http.ResponseWriter.WriteHeader in the same function body. This is most probably a bug."
+	_, _ = bloe.Write([]byte(`hellyelamdflmda`))     // want "function rwlExampleThree: Multiple calls to http.ResponseWriter.Write in the same function body. This is most probably a bug."
+	bloe.WriteHeader(http.StatusInternalServerError) // want "function rwlExampleThree: Multiple calls to http.ResponseWriter.WriteHeader in the same function body. This is most probably a bug."
+
+	bloe.Header().Set("help", "somebody")     // want "function rwlExampleThree: http.ResponseWriter.Header called after calling http.ResponseWriter.Write. This has no effect." "function rwlExampleThree: http.ResponseWriter.Header called after calling http.ResponseWriter.Write. This has no effect." "function rwlExampleThree: http.ResponseWriter.Header called after calling http.ResponseWriter.WriteHeader. This has no effect." "function rwlExampleThree: http.ResponseWriter.Header called after calling http.ResponseWriter.WriteHeader. This has no effect."
+	bloe.Header().Set("dddd", "someboddaady") // want "function rwlExampleThree: http.ResponseWriter.Header called after calling http.ResponseWriter.Write. This has no effect." "function rwlExampleThree: http.ResponseWriter.Header called after calling http.ResponseWriter.Write. This has no effect." "function rwlExampleThree: http.ResponseWriter.Header called after calling http.ResponseWriter.WriteHeader. This has no effect." "function rwlExampleThree: http.ResponseWriter.Header called after calling http.ResponseWriter.WriteHeader. This has no effect."
+}