Adding Validate() func to ConfigurationRequest along with test covera…

…ge (#150)

internal/teststep/config.go

@@ -6,12 +6,12 @@ package teststep
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"regexp"
-	"strings"
 )
 
 const (
@@ -42,31 +42,23 @@ type ConfigurationRequest struct {
 	Raw       *string
 }
 
-func Configuration(req ConfigurationRequest) (configuration, error) {
-	var populatedConfig []string
-	var config configuration
-
-	if req.Directory != nil && *req.Directory != "" {
-		populatedConfig = append(populatedConfig, fmt.Sprintf("%q", "directory"))
-
-		config = configuration{
-			directory: *req.Directory,
-		}
+func (c ConfigurationRequest) Validate() error {
+	if c.Directory != nil && c.Raw != nil && *c.Directory != "" && *c.Raw != "" {
+		return errors.New(`both "directory" and "raw" are populated, only one configuration option is allowed`)
 	}
 
-	if req.Raw != nil && *req.Raw != "" {
-		populatedConfig = append(populatedConfig, fmt.Sprintf("%q", "raw"))
+	return nil
+}
 
-		config = configuration{
-			raw: *req.Raw,
-		}
+func Configuration(req ConfigurationRequest) (configuration, error) {
+	var config configuration
+
+	if req.Directory != nil {
+		config.directory = *req.Directory
 	}
 
-	if len(populatedConfig) > 1 {
-		return configuration{}, fmt.Errorf(
-			"both %s are populated, only one configuration option is allowed",
-			strings.Join(populatedConfig, " and "),
-		)
+	if req.Raw != nil {
+		config.raw = *req.Raw
 	}
 
 	return config, nil

internal/teststep/config_test.go

@@ -6,8 +6,61 @@ package teststep
 import (
 	"context"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
+func TestConfigurationRequest_Validate(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		configRequest ConfigurationRequest
+		expectedError string
+	}{
+		"directory": {
+			configRequest: ConfigurationRequest{
+				Directory: Pointer("directory"),
+			},
+		},
+		"raw": {
+			configRequest: ConfigurationRequest{
+				Raw: Pointer("raw"),
+			},
+		},
+		"directory-raw": {
+			configRequest: ConfigurationRequest{
+				Directory: Pointer("directory"),
+				Raw:       Pointer("raw"),
+			},
+			expectedError: `both "directory" and "raw" are populated, only one configuration option is allowed`,
+		},
+	}
+
+	for name, testCase := range testCases {
+		name, testCase := name, testCase
+
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			err := testCase.configRequest.Validate()
+
+			if testCase.expectedError == "" && err != nil {
+				t.Errorf("unexpected error %s", err)
+			}
+
+			if testCase.expectedError != "" && err == nil {
+				t.Errorf("expected error but got none")
+			}
+
+			if testCase.expectedError != "" && err != nil {
+				if diff := cmp.Diff(err.Error(), testCase.expectedError); diff != "" {
+					t.Errorf("expected error %s, got error %s", testCase.expectedError, err)
+				}
+			}
+		})
+	}
+}
+
 func TestConfiguration_HasProviderBlock(t *testing.T) {
 	t.Parallel()