Custom formatting for slice type config attributes

config/config_attribute.go

@@ -122,7 +122,13 @@ func (a *ConfigAttribute) IsZero(cfg *Config) bool {
 func (a *ConfigAttribute) GetString(cfg *Config) string {
 	rv := reflect.ValueOf(cfg)
 	field := rv.Elem().Field(a.num)
-	return fmt.Sprintf("%v", field.Interface())
+	switch a.Kind {
+	case reflect.Slice:
+		parts := field.Interface().([]string)
+		return strings.Join(parts, ",")
+	default:
+		return fmt.Sprintf("%v", field.Interface())
+	}
 }
 
 func (a *ConfigAttribute) HasAuthAttribute() bool {

config/config_attributes_test.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"reflect"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -59,3 +60,107 @@ func TestConfigFile_Configure_ListParsing(t *testing.T) {
 		})
 	}
 }
+
+func TestConfigAttribute_GetString(t *testing.T) {
+	findAttr := func(name string) *ConfigAttribute {
+		for i := range ConfigAttributes {
+			if ConfigAttributes[i].Name == name {
+				return &ConfigAttributes[i]
+			}
+		}
+		t.Fatalf("attribute %q not found", name)
+		return nil
+	}
+
+	testCases := []struct {
+		name     string
+		attrName string
+		wantKind reflect.Kind
+		cfg      *Config
+		want     string
+	}{
+		{
+			name:     "string type returns string value",
+			attrName: "host",
+			wantKind: reflect.String,
+			cfg:      &Config{Host: "https://example.databricks.com"},
+			want:     "https://example.databricks.com",
+		},
+		{
+			name:     "string type returns empty string when not set",
+			attrName: "host",
+			wantKind: reflect.String,
+			cfg:      &Config{},
+			want:     "",
+		},
+		{
+			name:     "bool type returns true",
+			attrName: "skip_verify",
+			wantKind: reflect.Bool,
+			cfg:      &Config{InsecureSkipVerify: true},
+			want:     "true",
+		},
+		{
+			name:     "bool type returns false",
+			attrName: "skip_verify",
+			wantKind: reflect.Bool,
+			cfg:      &Config{InsecureSkipVerify: false},
+			want:     "false",
+		},
+		{
+			name:     "int type returns numeric string",
+			attrName: "http_timeout_seconds",
+			wantKind: reflect.Int,
+			cfg:      &Config{HTTPTimeoutSeconds: 120},
+			want:     "120",
+		},
+		{
+			name:     "int type returns zero",
+			attrName: "http_timeout_seconds",
+			wantKind: reflect.Int,
+			cfg:      &Config{HTTPTimeoutSeconds: 0},
+			want:     "0",
+		},
+		{
+			name:     "slice type returns comma-joined string",
+			attrName: "scopes",
+			wantKind: reflect.Slice,
+			cfg:      &Config{Scopes: []string{"alpha", "beta", "gamma"}},
+			want:     "alpha,beta,gamma",
+		},
+		{
+			name:     "slice type returns single item",
+			attrName: "scopes",
+			wantKind: reflect.Slice,
+			cfg:      &Config{Scopes: []string{"all-apis"}},
+			want:     "all-apis",
+		},
+		{
+			name:     "slice type returns empty string for nil slice",
+			attrName: "scopes",
+			wantKind: reflect.Slice,
+			cfg:      &Config{Scopes: nil},
+			want:     "",
+		},
+		{
+			name:     "slice type returns empty string for empty slice",
+			attrName: "scopes",
+			wantKind: reflect.Slice,
+			cfg:      &Config{Scopes: []string{}},
+			want:     "",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			attr := findAttr(tc.attrName)
+			if attr.Kind != tc.wantKind {
+				t.Fatalf("expected %v kind, got %v", tc.wantKind, attr.Kind)
+			}
+			got := attr.GetString(tc.cfg)
+			if got != tc.want {
+				t.Errorf("GetString() = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}