feat: Add support for update checks and notifications (#4810)

Co-authored-by: Kira Pilot <kira@coder.com>

coderd/updatecheck_test.go

@@ -0,0 +1,79 @@
+package coderd_test
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/google/go-github/v43/github"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/buildinfo"
+	"github.com/coder/coder/coderd/coderdtest"
+	"github.com/coder/coder/coderd/updatecheck"
+	"github.com/coder/coder/codersdk"
+	"github.com/coder/coder/testutil"
+)
+
+func TestUpdateCheck_NewVersion(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name string
+		resp github.RepositoryRelease
+		want codersdk.UpdateCheckResponse
+	}{
+		{
+			name: "New version",
+			resp: github.RepositoryRelease{
+				TagName: github.String("v99.999.999"),
+				HTMLURL: github.String("https://someurl.com"),
+			},
+			want: codersdk.UpdateCheckResponse{
+				Current: false,
+				Version: "v99.999.999",
+				URL:     "https://someurl.com",
+			},
+		},
+		{
+			name: "Same version",
+			resp: github.RepositoryRelease{
+				TagName: github.String(buildinfo.Version()),
+				HTMLURL: github.String("https://someurl.com"),
+			},
+			want: codersdk.UpdateCheckResponse{
+				Current: true,
+				Version: buildinfo.Version(),
+				URL:     "https://someurl.com",
+			},
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+				b, err := json.Marshal(tt.resp)
+				assert.NoError(t, err)
+				w.Write(b)
+			}))
+			defer srv.Close()
+
+			client := coderdtest.New(t, &coderdtest.Options{
+				UpdateCheckOptions: &updatecheck.Options{
+					URL: srv.URL,
+				},
+			})
+
+			ctx, _ := testutil.Context(t)
+
+			got, err := client.UpdateCheck(ctx)
+			require.NoError(t, err)
+			require.Equal(t, tt.want, got)
+		})
+	}
+}