fix: prevent TestVSCode from writing to real settings.json

TestVSCode runs the full command via TestCmd which calls
createConnectionProfile -> getVSCodeSettingsPath, resolving to the
real %APPDATA%\Code\User\settings.json. This silently mutates the
developer's actual VS Code settings on every test run.

Add testSettingsPathOverride hook so TestVSCode redirects writes to
t.TempDir(). The hook is cleared in t.Cleanup so other tests like
TestVSCodeGetSettingsPath still exercise the real path resolution.

Author: dlevy-msft-sql

cmd/modern/root/open/vscode.go

@@ -20,6 +20,10 @@ import (
 	"github.com/microsoft/go-sqlcmd/internal/tools/tool"
 )
 
+// testSettingsPathOverride, when non-empty, overrides getVSCodeSettingsPath
+// so tests never touch the real VS Code settings.json.
+var testSettingsPathOverride string
+
 // VSCode implements the `sqlcmd open vscode` command. It opens
 // Visual Studio Code and configures a connection profile for the
 // current context using the MSSQL extension.
@@ -281,6 +285,10 @@ func (c *VSCode) updateOrAddProfile(connections []interface{}, newProfile map[st
 }
 
 func (c *VSCode) getVSCodeSettingsPath() string {
+	if testSettingsPathOverride != "" {
+		return testSettingsPathOverride
+	}
+
 	var stableDir string
 	var insidersDir string
 

cmd/modern/root/open/vscode_test.go

@@ -28,6 +28,11 @@ func TestVSCode(t *testing.T) {
 		t.Skip("VS Code is not installed")
 	}
 
+	// Redirect settings writes to a temp directory so the test never
+	// touches the real VS Code settings.json.
+	testSettingsPathOverride = filepath.Join(t.TempDir(), "settings.json")
+	t.Cleanup(func() { testSettingsPathOverride = "" })
+
 	cmdparser.TestSetup(t)
 	config.AddEndpoint(sqlconfig.Endpoint{
 		AssetDetails: nil,