Writing tests for Render package

internal/render/render.go

@@ -2,6 +2,7 @@ package render
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"go-udemy-web-1/internal/config"
 	"go-udemy-web-1/internal/models"
@@ -35,7 +36,7 @@ func AddDefaultData(td *models.TemplateData, r *http.Request) *models.TemplateDa
 }
 
 // RenderTemplate renders a HTML template file
-func RenderTemplate(w http.ResponseWriter, r *http.Request, tmpl string, td *models.TemplateData) {
+func RenderTemplate(w http.ResponseWriter, r *http.Request, tmpl string, td *models.TemplateData) error {
 	var tc map[string]*template.Template
 	if app.UseCache {
 		// get the template cache from the app config
@@ -47,7 +48,7 @@ func RenderTemplate(w http.ResponseWriter, r *http.Request, tmpl string, td *mod
 	// get requested template from cache
 	t, ok := tc[tmpl]
 	if !ok {
-		log.Fatal("Could not get template from template cache")
+		return errors.New("could not get template from template cache")
 	}
 
 	// Write to a buffer to make sure that the template can be read and
@@ -59,13 +60,17 @@ func RenderTemplate(w http.ResponseWriter, r *http.Request, tmpl string, td *mod
 	err := t.Execute(buf, td)
 	if err != nil {
 		log.Println(err)
+		return err
 	}
 
 	// render the template
 	_, err = buf.WriteTo(w)
 	if err != nil {
 		log.Println(err)
+		return err
 	}
+
+	return nil
 }
 
 func CreateTemplateCache() (map[string]*template.Template, error) {

internal/render/render_test.go

@@ -0,0 +1,76 @@
+package render
+
+import (
+	"go-udemy-web-1/internal/models"
+	"net/http"
+	"testing"
+)
+
+func TestAddDefaultData(t *testing.T) {
+	var td models.TemplateData
+
+	r, err := getSession()
+	if err != nil {
+		t.Error(err)
+	}
+
+	session.Put(r.Context(), "flash", "123")
+
+	result := AddDefaultData(&td, r)
+
+	if result.Flash != "123" {
+		t.Error("flash value of 123 not found in session")
+	}
+}
+
+func TestRenderTemplate(t *testing.T) {
+	pathToTemplates = "../../templates"
+	tc, err := CreateTemplateCache()
+	if err != nil {
+		t.Error(err)
+	}
+
+	app.TemplateCahce = tc
+
+	r, err := getSession()
+	if err != nil {
+		t.Error(err)
+	}
+
+	var ww myWriter
+
+	err = RenderTemplate(&ww, r, "home.page.tmpl", &models.TemplateData{})
+	if err != nil {
+		t.Error("error writiing template to browser")
+	}
+
+	err = RenderTemplate(&ww, r, "non-existent.page.html", &models.TemplateData{})
+	if err == nil {
+		t.Error("rendered template that doesn't exist")
+	}
+}
+
+func getSession() (*http.Request, error) {
+	r, err := http.NewRequest("GET", "/some-url", nil)
+	if err != nil {
+		return nil, err
+	}
+
+	ctx := r.Context()
+	ctx, _ = session.Load(ctx, r.Header.Get("X-Session"))
+	r = r.WithContext(ctx)
+
+	return r, nil
+}
+
+func TestNewTemplate(t *testing.T) {
+	NewTemplates(app)
+}
+
+func TestCreateTemplateCache(t *testing.T) {
+	pathToTemplates = "../../templates"
+	_, err := CreateTemplateCache()
+	if err != nil {
+		t.Error(err)
+	}
+}

internal/render/setup_test.go

@@ -0,0 +1,52 @@
+package render
+
+import (
+	"encoding/gob"
+	"go-udemy-web-1/internal/config"
+	"go-udemy-web-1/internal/models"
+	"net/http"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/alexedwards/scs/v2"
+)
+
+var (
+	session *scs.SessionManager
+	testApp config.AppConfig
+)
+
+func TestMain(m *testing.M) {
+	// what am I going to put in the session
+	gob.Register(models.Reservation{})
+
+	// change this to true when in production
+	testApp.InProduction = false
+
+	session = scs.New()
+	session.Lifetime = 24 * time.Hour
+	session.Cookie.Persist = true
+	session.Cookie.SameSite = http.SameSiteLaxMode
+	session.Cookie.Secure = testApp.InProduction
+
+	testApp.Session = session
+
+	app = &testApp
+
+	os.Exit(m.Run())
+}
+
+type myWriter struct{}
+
+func (tw *myWriter) Header() http.Header {
+	var h http.Header
+	return h
+}
+
+func (tw *myWriter) WriteHeader(i int) {}
+
+func (tw *myWriter) Write(b []byte) (int, error) {
+	length := len(b)
+	return length, nil
+}