test(config): additional test cases for config errors

Relates to #131

pkg/config/config_test.go

@@ -3,14 +3,53 @@ package config
 import (
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 )
 
-func TestReadConfig(t *testing.T) {
-	tempDir := t.TempDir()
+func TestReadConfigMissingFile(t *testing.T) {
+	config, err := ReadConfig("non-existent-config.toml")
+	t.Run("returns error for missing file", func(t *testing.T) {
+		if err == nil {
+			t.Fatal("Expected error for missing file, got nil")
+		}
+		if config != nil {
+			t.Fatalf("Expected nil config for missing file, got %v", config)
+		}
+	})
+}
 
-	t.Run("ValidConfigFileWithDeniedResources", func(t *testing.T) {
-		validConfigContent := `
+func TestReadConfigInvalid(t *testing.T) {
+	invalidConfigPath := writeConfig(t, `
+[[denied_resources]]
+group = "apps"
+version = "v1"
+kind = "Deployment"
+[[denied_resources]]
+group = "rbac.authorization.k8s.io"
+version = "v1"
+kind = "Role
+`)
+
+	config, err := ReadConfig(invalidConfigPath)
+	t.Run("returns error for invalid file", func(t *testing.T) {
+		if err == nil {
+			t.Fatal("Expected error for invalid file, got nil")
+		}
+		if config != nil {
+			t.Fatalf("Expected nil config for invalid file, got %v", config)
+		}
+	})
+	t.Run("error message contains toml error with line number", func(t *testing.T) {
+		expectedError := "toml: line 9"
+		if err != nil && !strings.HasPrefix(err.Error(), expectedError) {
+			t.Fatalf("Expected error message '%s' to contain line number, got %v", expectedError, err)
+		}
+	})
+}
+
+func TestReadConfigValid(t *testing.T) {
+	validConfigPath := writeConfig(t, `
 [[denied_resources]]
 group = "apps"
 version = "v1"
@@ -19,26 +58,21 @@ kind = "Deployment"
 [[denied_resources]]
 group = "rbac.authorization.k8s.io"
 version = "v1"
-`
-		validConfigPath := filepath.Join(tempDir, "valid_denied_config.toml")
-		err := os.WriteFile(validConfigPath, []byte(validConfigContent), 0644)
-		if err != nil {
-			t.Fatalf("Failed to write valid config file: %v", err)
-		}
+`)
 
-		config, err := ReadConfig(validConfigPath)
+	config, err := ReadConfig(validConfigPath)
+	t.Run("reads and unmarshalls file", func(t *testing.T) {
 		if err != nil {
 			t.Fatalf("ReadConfig returned an error for a valid file: %v", err)
 		}
-
 		if config == nil {
 			t.Fatal("ReadConfig returned a nil config for a valid file")
 		}
-
+	})
+	t.Run("denied resources are parsed correctly", func(t *testing.T) {
 		if len(config.DeniedResources) != 2 {
 			t.Fatalf("Expected 2 denied resources, got %d", len(config.DeniedResources))
 		}
-
 		if config.DeniedResources[0].Group != "apps" ||
 			config.DeniedResources[0].Version != "v1" ||
 			config.DeniedResources[0].Kind != "Deployment" {
@@ -46,3 +80,14 @@ version = "v1"
 		}
 	})
 }
+
+func writeConfig(t *testing.T, content string) string {
+	t.Helper()
+	tempDir := t.TempDir()
+	path := filepath.Join(tempDir, "config.toml")
+	err := os.WriteFile(path, []byte(content), 0644)
+	if err != nil {
+		t.Fatalf("Failed to write config file %s: %v", path, err)
+	}
+	return path
+}

pkg/kubernetes-mcp-server/cmd/root_test.go

@@ -66,6 +66,19 @@ func TestConfig(t *testing.T) {
 			t.Fatalf("Expected config to be %s, got %s %v", expected, out.String(), err)
 		}
 	})
+	t.Run("invalid path throws error", func(t *testing.T) {
+		ioStreams, _ := testStream()
+		rootCmd := NewMCPServer(ioStreams)
+		rootCmd.SetArgs([]string{"--version", "--log-level=1", "--config", "invalid-path-to-config.toml"})
+		err := rootCmd.Execute()
+		if err == nil {
+			t.Fatal("Expected error for invalid config path, got nil")
+		}
+		expected := "open invalid-path-to-config.toml: "
+		if !strings.HasPrefix(err.Error(), expected) {
+			t.Fatalf("Expected error to be %s, got %s", expected, err.Error())
+		}
+	})
 }
 
 func TestProfile(t *testing.T) {