Add basic test demonstrating handler and middleware testing

internal/server/handler_test.go

@@ -0,0 +1,49 @@
+package server
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"git.runcible.io/learning/ratchet/internal/assert"
+)
+
+func TestPing(t *testing.T) {
+	// This is essentially an implementation of http.ResponseWriter
+	// which records the response status code, headers and body instead
+	// of actually writing them to a HTTP connection.
+	rr := httptest.NewRecorder()
+
+	// Initialize a dummy request
+	r, err := http.NewRequest(http.MethodGet, "/", nil)
+	if err != nil {
+		// When called, t.Fatal() will mark the test as failed, log the error,
+		//  and then completely stop execution of the current test
+		// (or sub-test).
+
+		// Typically you should call t.Fatal() in situations where it doesn’t
+		// make sense to continue the current test — such as an error during
+		// a setup step, or where an unexpected error from a Go standard
+		// library function means you can’t proceed with the test.
+		t.Fatal(err)
+	}
+	ping := PingHandler()
+	ping.ServeHTTP(rr, r)
+
+	resp := rr.Result()
+
+	assert.Equal(t, resp.StatusCode, http.StatusOK)
+
+	defer resp.Body.Close()
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	body = bytes.TrimSpace(body)
+
+	assert.Equal(t, string(body), "OK")
+
+}

internal/server/handlers.go

@@ -444,3 +444,9 @@ func handleUserLogoutPost(logger *slog.Logger, sm *scs.SessionManager) http.Hand
 		http.Redirect(w, r, "/", http.StatusSeeOther)
 	})
 }
+
+func PingHandler() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("OK"))
+	})
+}

internal/server/middleware_test.go

@@ -0,0 +1,77 @@
+package server
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"git.runcible.io/learning/ratchet/internal/assert"
+)
+
+func TestCommonHeadersMiddleware(t *testing.T) {
+	rr := httptest.NewRecorder()
+
+	r, err := http.NewRequest(http.MethodGet, "/", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// mock http.Handler
+	next := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("OK"))
+	})
+
+	// Pass the mock HTTP handler to our commonHeaders middleware. Because
+	// commonHeaders *returns* a http.Handler we can call its ServeHTTP()
+	// method, passing in the http.ResponseRecorder and dummy http.Request to
+	// execute it.
+	CommonHeaderMiddleware(next).ServeHTTP(rr, r)
+
+	resp := rr.Result()
+
+	// Check that the middleware has correctly set the Content-Security-Policy
+	// header on the response.
+	expectedValue := "default-src 'self'; style-src 'self' fonts.googleapis.com; font-src fonts.gstatic.com"
+	assert.Equal(t, resp.Header.Get("Content-Security-Policy"), expectedValue)
+
+	// Check that the middleware has correctly set the Referrer-Policy
+	// header on the response.
+	expectedValue = "origin-when-cross-origin"
+	assert.Equal(t, resp.Header.Get("Referrer-Policy"), expectedValue)
+
+	// Check that the middleware has correctly set the X-Content-Type-Options
+	// header on the response.
+	expectedValue = "nosniff"
+	assert.Equal(t, resp.Header.Get("X-Content-Type-Options"), expectedValue)
+
+	// Check that the middleware has correctly set the X-Frame-Options header
+	// on the response.
+	expectedValue = "deny"
+	assert.Equal(t, resp.Header.Get("X-Frame-Options"), expectedValue)
+
+	// Check that the middleware has correctly set the X-XSS-Protection header
+	// on the response
+	expectedValue = "0"
+	assert.Equal(t, resp.Header.Get("X-XSS-Protection"), expectedValue)
+
+	// Check that the middleware has correctly set the Server header on the
+	// response.
+	expectedValue = "Go"
+	assert.Equal(t, resp.Header.Get("Server"), expectedValue)
+
+	// Check that the middleware has correctly called the next handler in line
+	// and the response status code and body are as expected.
+	assert.Equal(t, resp.StatusCode, http.StatusOK)
+
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	body = bytes.TrimSpace(body)
+
+	assert.Equal(t, string(body), "OK")
+}