diff --git a/internal/github/client.go b/internal/github/client.go
index 8a597c8..61c8faa 100644
--- a/internal/github/client.go
+++ b/internal/github/client.go
@@ -12,6 +12,12 @@ import (
 	"github.com/ntsk/gh-issue-bulk-create/pkg/models"
 )
 
+// ClientInterface defines the interface for GitHub API operations
+type ClientInterface interface {
+	CreateIssue(issue *models.Issue, repo string) (*models.IssueResponse, error)
+	GetCurrentRepository() (string, error)
+}
+
 // Client provides GitHub API functionality
 type Client struct {
 	client *api.RESTClient
@@ -88,29 +94,3 @@ func (c *Client) GetCurrentRepository() (string, error) {
 
 	return fmt.Sprintf("%s/%s", info.Owner.Login, info.Name), nil
 }
-
-// MockClient provides a mock GitHub client for testing
-type MockClient struct {
-	CreateIssueFunc       func(issue *models.Issue, repo string) (*models.IssueResponse, error)
-	GetCurrentRepoFunc    func() (string, error)
-	CreatedIssues         []*models.Issue
-	GetCurrentRepoCounter int
-}
-
-// CreateIssue implements the Client interface for testing
-func (m *MockClient) CreateIssue(issue *models.Issue, repo string) (*models.IssueResponse, error) {
-	m.CreatedIssues = append(m.CreatedIssues, issue)
-	if m.CreateIssueFunc != nil {
-		return m.CreateIssueFunc(issue, repo)
-	}
-	return &models.IssueResponse{Number: 1, URL: "https://github.com/mock/repo/issues/1"}, nil
-}
-
-// GetCurrentRepository implements the Client interface for testing
-func (m *MockClient) GetCurrentRepository() (string, error) {
-	m.GetCurrentRepoCounter++
-	if m.GetCurrentRepoFunc != nil {
-		return m.GetCurrentRepoFunc()
-	}
-	return "mock/repo", nil
-}
diff --git a/internal/github/client_test.go b/internal/github/client_test.go
index f80e7cc..626febc 100644
--- a/internal/github/client_test.go
+++ b/internal/github/client_test.go
@@ -6,6 +6,32 @@ import (
 	"github.com/ntsk/gh-issue-bulk-create/pkg/models"
 )
 
+// MockClient provides a mock GitHub client for testing
+type MockClient struct {
+	CreateIssueFunc       func(issue *models.Issue, repo string) (*models.IssueResponse, error)
+	GetCurrentRepoFunc    func() (string, error)
+	CreatedIssues         []*models.Issue
+	GetCurrentRepoCounter int
+}
+
+// CreateIssue implements the ClientInterface for testing
+func (m *MockClient) CreateIssue(issue *models.Issue, repo string) (*models.IssueResponse, error) {
+	m.CreatedIssues = append(m.CreatedIssues, issue)
+	if m.CreateIssueFunc != nil {
+		return m.CreateIssueFunc(issue, repo)
+	}
+	return &models.IssueResponse{Number: 1, URL: "https://github.com/mock/repo/issues/1"}, nil
+}
+
+// GetCurrentRepository implements the ClientInterface for testing
+func (m *MockClient) GetCurrentRepository() (string, error) {
+	m.GetCurrentRepoCounter++
+	if m.GetCurrentRepoFunc != nil {
+		return m.GetCurrentRepoFunc()
+	}
+	return "mock/repo", nil
+}
+
 func TestMockClient(t *testing.T) {
 	// Create mock client
 	mockClient := &MockClient{}
@@ -70,3 +96,33 @@ func TestMockClient(t *testing.T) {
 		t.Errorf("Expected custom repo 'custom/repo', got '%s'", repo)
 	}
 }
+
+// TestClientInterface demonstrates that MockClient implements ClientInterface
+func TestClientInterface(t *testing.T) {
+	// Verify that MockClient implements the interface by using it
+	var client ClientInterface = &MockClient{}
+
+	// Test that we can call interface methods
+	issue := &models.Issue{
+		Title: "Interface Test",
+		Body:  "Testing interface implementation",
+	}
+
+	response, err := client.CreateIssue(issue, "test/repo")
+	if err != nil {
+		t.Errorf("Expected no error, got: %v", err)
+	}
+
+	if response.Number != 1 {
+		t.Errorf("Expected issue number 1, got %d", response.Number)
+	}
+
+	repo, err := client.GetCurrentRepository()
+	if err != nil {
+		t.Errorf("Expected no error, got: %v", err)
+	}
+
+	if repo != "mock/repo" {
+		t.Errorf("Expected repo 'mock/repo', got '%s'", repo)
+	}
+}