chore: check config field validation patterns compile in Go

pkg/templates/config_test.go

@@ -0,0 +1,49 @@
+package templates_test
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/speakeasy-api/openapi-generation/v2/internal/types"
+	"github.com/speakeasy-api/openapi-generation/v2/pkg/templates"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// RegExp.source emits "/" as the Unicode escape below, which the CLI rewrites before compiling the pattern with Go's regexp.
+const escapedSlash = "\x5cu002f"
+
+func TestConfigFieldValidationRegexes(t *testing.T) {
+	t.Parallel()
+
+	for _, name := range templates.GetAvailableTemplates() {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			for _, newSDK := range []bool{false, true} {
+				fields, err := templates.GetLanguageConfigFields(types.NewTargetFromTemplate(name), newSDK)
+				require.NoError(t, err)
+
+				for _, field := range fields {
+					if field.ValidationRegex == nil {
+						continue
+					}
+
+					pattern := strings.ReplaceAll(*field.ValidationRegex, escapedSlash, "/")
+					regex, err := regexp.Compile(pattern)
+					require.NoError(t, err, "field %q (newSDK=%v)", field.Name, newSDK)
+
+					if field.DefaultValue == nil {
+						continue
+					}
+
+					defaultValue := fmt.Sprintf("%v", *field.DefaultValue)
+					assert.True(t, regex.MatchString(defaultValue),
+						"field %q (newSDK=%v): default %q does not match %s", field.Name, newSDK, defaultValue, pattern)
+				}
+			}
+		})
+	}
+}