🌱 Included tests for accessor (#3178)

* 🌱 Included tests for accessor

- Add test file for Token Accessor

Signed-off-by: naveensrinivasan <172697+naveensrinivasan@users.noreply.github.com>

* Code review comments.

Signed-off-by: naveensrinivasan <172697+naveensrinivasan@users.noreply.github.com>

---------

Signed-off-by: naveensrinivasan <172697+naveensrinivasan@users.noreply.github.com>

clients/githubrepo/roundtripper/tokens/accessor_test.go

@@ -0,0 +1,129 @@
+// Copyright 2023 OpenSSF Scorecard Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package tokens
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net/http"
+	"net/rpc"
+	"testing"
+)
+
+//nolint:paralleltest
+func TestMakeTokenAccessor(t *testing.T) {
+	tests := []struct {
+		name           string
+		useGitHubToken bool
+		useServer      bool
+	}{
+		{
+			name:           "GitHub Token",
+			useGitHubToken: true,
+		},
+		{
+			name:           "No GitHub Token",
+			useGitHubToken: false,
+		},
+		{
+			name:      "Server",
+			useServer: true,
+		},
+	}
+	t.Setenv("GITHUB_AUTH_TOKEN", "")
+	t.Setenv("GITHUB_TOKEN", "")
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			switch {
+			case tt.useGitHubToken:
+				t.Helper()
+				testToken(t)
+			case tt.useServer:
+				t.Helper()
+				testServer(t)
+			default:
+				got := MakeTokenAccessor()
+				if got != nil {
+					t.Errorf("MakeTokenAccessor() = %v, want nil", got)
+				}
+			}
+		})
+	}
+}
+
+func testToken(t *testing.T) {
+	t.Helper()
+	token := "test"
+	t.Setenv("GITHUB_AUTH_TOKEN", token)
+	got := MakeTokenAccessor()
+	if got == nil {
+		t.Errorf("MakeTokenAccessor() = nil, want not nil")
+	}
+	raccess, ok := got.(*roundRobinAccessor)
+	if !ok {
+		t.Errorf("MakeTokenAccessor() = %v, want *roundRobinAccessor", got)
+	}
+	if raccess.accessTokens[0] != token {
+		t.Errorf("accessTokens[0] = %v, want %v", raccess.accessTokens[0], token)
+	}
+}
+
+func testServer(t *testing.T) {
+	t.Helper()
+	t.Setenv("GITHUB_AUTH_SERVER", "localhost:8080")
+	server := startTestServer()
+	t.Cleanup(func() {
+		serverShutdown(server)
+	})
+	myRPCService := &MyRPCService{}
+	rpc.Register(myRPCService) //nolint:errcheck
+	server.Handler = nil
+	rpc.HandleHTTP()
+	got := MakeTokenAccessor()
+	if got == nil {
+		t.Errorf("MakeTokenAccessor() = nil, want not nil")
+	}
+}
+
+type MyRPCService struct {
+	// Define your RPC service methods here
+}
+
+func startTestServer() *http.Server {
+	// Create a new server
+	server := &http.Server{ //nolint:gosec
+		Addr:    ":8080",
+		Handler: nil, // Use the default handler
+	}
+
+	// Start the server in a separate goroutine
+	go func() {
+		fmt.Println("Starting server on http://localhost:8080")
+		if err := server.ListenAndServe(); err != nil && !errors.Is(http.ErrServerClosed, err) {
+			log.Fatal(err)
+		}
+	}()
+
+	return server
+}
+
+func serverShutdown(server *http.Server) {
+	err := server.Close()
+	if err != nil {
+		log.Fatalf("Error shutting down server: %s\n", err.Error())
+	}
+
+	fmt.Println("Server gracefully stopped")
+}