Fix: filter out \ args when no test name is available

When getCTestArgs is called without a specific test name (e.g., during
test discovery, batch runs, or initial configuration), args containing
\ are now filtered out instead of being passed to ctest with
the literal unexpanded placeholder. This prevents creating files with
literal \ in their name.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Omotola

src/ctest.ts

@@ -459,8 +459,15 @@ export class CTestDriver implements vscode.Disposable {
         const opts: ExpansionOptions = testName !== undefined
             ? { ...driver.expansionOptions, vars: { ...driver.expansionOptions.vars, testName } }
             : driver.expansionOptions;
-        const initialArgs = await Promise.all(this.ws.config.ctestDefaultArgs.map(async (value) => expandString(value, opts)));
-        const additionalArgs = await Promise.all(this.ws.config.ctestArgs.map(async (value) => expandString(value, opts)));
+
+        // When testName is not provided, filter out args containing ${testName} to avoid
+        // passing literal "${testName}" to ctest (e.g., during test discovery or batch runs).
+        const testNamePlaceholder = '${testName}';
+        const filterTestNameArgs = (args: string[]): string[] =>
+            testName !== undefined ? args : args.filter(arg => !arg.includes(testNamePlaceholder));
+
+        const initialArgs = await Promise.all(filterTestNameArgs(this.ws.config.ctestDefaultArgs).map(async (value) => expandString(value, opts)));
+        const additionalArgs = await Promise.all(filterTestNameArgs(this.ws.config.ctestArgs).map(async (value) => expandString(value, opts)));
 
         ctestArgs = initialArgs.slice(0);