feat: option to disable source tracking on scratch orgs (#470)

src/testSession.ts

@@ -41,6 +41,8 @@ export type ScratchOrgConfig = {
     | 'partner-professional';
   username?: string;
   wait?: number;
+  /** true by default. Has no effect unless you set it to false */
+  tracksSource?: boolean;
 };
 
 export interface TestSessionOptions {
@@ -353,6 +355,11 @@ export class TestSession<T extends TestSessionOptions = TestSessionOptions> exte
           baseCmd += ` -e ${org.edition}`;
         }
 
+        // explicitly disable tracking only if set to false.  True is the default on the command
+        if (org.tracksSource === false) {
+          baseCmd += ' --no-track-source';
+        }
+
         const rv = shell.exec(baseCmd, this.shelljsExecOptions) as shell.ShellString;
         rv.stdout = stripAnsi(rv.stdout);
         rv.stderr = stripAnsi(rv.stderr);