Fix install page context, make the install page tests really test (#24858)

Fix #24856

Rename "context.contextKey" to "context.WebContextKey", this context is
for web context only. But the Context itself is not renamed, otherwise
it would cause a lot of changes (if we really want to rename it, there
could be a separate PR).

The old test code doesn't really test, the "install page" gets broken
not only one time, so use new test code to make sure the "install page"
could work.

routers/install/routes_test.go

@@ -1,24 +1,41 @@
-// Copyright 2021 The Gitea Authors. All rights reserved.
+// Copyright 2023 The Gitea Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
 package install
 
 import (
-	"context"
+	"net/http/httptest"
+	"path/filepath"
 	"testing"
 
+	"code.gitea.io/gitea/models/unittest"
+
 	"github.com/stretchr/testify/assert"
 )
 
 func TestRoutes(t *testing.T) {
-	// TODO: this test seems not really testing the handlers
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-	base := Routes(ctx)
-	assert.NotNil(t, base)
-	r := base.R.Routes()[1]
-	routes := r.SubRoutes.Routes()[0]
-	assert.EqualValues(t, "/", routes.Pattern)
-	assert.Nil(t, routes.SubRoutes)
-	assert.Len(t, routes.Handlers, 2)
+	r := Routes()
+	assert.NotNil(t, r)
+
+	w := httptest.NewRecorder()
+	req := httptest.NewRequest("GET", "/", nil)
+	r.ServeHTTP(w, req)
+	assert.EqualValues(t, 200, w.Code)
+	assert.Contains(t, w.Body.String(), `class="page-content install"`)
+
+	w = httptest.NewRecorder()
+	req = httptest.NewRequest("GET", "/no-such", nil)
+	r.ServeHTTP(w, req)
+	assert.EqualValues(t, 404, w.Code)
+
+	w = httptest.NewRecorder()
+	req = httptest.NewRequest("GET", "/assets/img/gitea.svg", nil)
+	r.ServeHTTP(w, req)
+	assert.EqualValues(t, 200, w.Code)
+}
+
+func TestMain(m *testing.M) {
+	unittest.MainTest(m, &unittest.TestOptions{
+		GiteaRootPath: filepath.Join("..", ".."),
+	})
 }