diff --git a/src/commands/test.ts b/src/commands/test.ts
index d070c9aa..808e020d 100644
--- a/src/commands/test.ts
+++ b/src/commands/test.ts
@@ -89,7 +89,7 @@ export async function testSolution(uri?: vscode.Uri): Promise<void> {
 
 function parseTestString(test: string): string {
     if (wsl.useWsl() || !isWindows()) {
-        return `'${test}'`;
+        return `'${test.replace(/'/g, "'\\''")}'`;
     }
 
     // In windows and not using WSL
@@ -97,6 +97,6 @@ function parseTestString(test: string): string {
         return `"${test.replace(/"/g, '\\"')}"`;
     } else {
         // Assume using PowerShell
-        return `'${test.replace(/"/g, '\\"')}'`;
+        return `'${test.replace(/'/g, "''")}'`;
     }
 }
diff --git a/test/quoting-receiver.js b/test/quoting-receiver.js
new file mode 100644
index 00000000..e18dc572
--- /dev/null
+++ b/test/quoting-receiver.js
@@ -0,0 +1,2 @@
+// Helper for verify-quoting.js — prints argv as JSON
+process.stdout.write(JSON.stringify(process.argv.slice(2)));
diff --git a/test/verify-quoting.js b/test/verify-quoting.js
new file mode 100644
index 00000000..f140b085
--- /dev/null
+++ b/test/verify-quoting.js
@@ -0,0 +1,146 @@
+// Regression test for parseTestString quoting (src/commands/test.ts)
+// Run: node test/verify-quoting.js
+
+"use strict";
+
+const cp = require("child_process");
+const path = require("path");
+
+// ---------- parseTestString (mirrors src/commands/test.ts) ----------
+
+function parseTestString_bash(test) {
+    return "'" + test.replace(/'/g, "'\\''") + "'";
+}
+
+function parseTestString_cmd(test) {
+    return '"' + test.replace(/"/g, '\\"') + '"';
+}
+
+// ---------- test helpers ----------
+
+const RECEIVER = path.join(__dirname, "quoting-receiver.js");
+const RECEIVER_POSIX = RECEIVER.replace(/\\/g, "/");
+
+function spawnTestBash(parsed) {
+    return new Promise(function (resolve) {
+        var cmd = "node " + JSON.stringify(RECEIVER_POSIX) + " -t " + parsed;
+        var stdout = "";
+        var stderr = "";
+        var child = cp.spawn("bash", ["-c", cmd]);
+        child.stdout.on("data", function (d) { stdout += d; });
+        child.stderr.on("data", function (d) { stderr += d; });
+        child.on("error", function (err) {
+            resolve({ exitCode: -1, received: null, stderr: err.message });
+        });
+        child.on("close", function (code) {
+            var received = null;
+            try {
+                var arr = JSON.parse(stdout);
+                var idx = arr.indexOf("-t");
+                if (idx >= 0) received = arr[idx + 1];
+            } catch (_) { /* parse failure */ }
+            resolve({ exitCode: code, received: received, stderr: stderr.trim().split("\n")[0] });
+        });
+    });
+}
+
+function spawnTestCmd(parsed) {
+    return new Promise(function (resolve) {
+        var stdout = "";
+        var stderr = "";
+        var child = cp.spawn("node", ['"' + RECEIVER + '"', "-t", parsed], { shell: true });
+        child.stdout.on("data", function (d) { stdout += d; });
+        child.stderr.on("data", function (d) { stderr += d; });
+        child.on("error", function (err) {
+            resolve({ exitCode: -1, received: null, stderr: err.message });
+        });
+        child.on("close", function (code) {
+            var received = null;
+            try {
+                var arr = JSON.parse(stdout);
+                var idx = arr.indexOf("-t");
+                if (idx >= 0) received = arr[idx + 1];
+            } catch (_) { /* parse failure */ }
+            resolve({ exitCode: code, received: received, stderr: stderr.trim().split("\n")[0] });
+        });
+    });
+}
+
+var TEST_CASES = [
+    { input: "[1,2,3]",           desc: "numeric array" },
+    { input: '"hello"',           desc: "double quotes" },
+    { input: "it's",              desc: "embedded single quote" },
+    { input: "['a','b']",         desc: "array with single-quoted chars" },
+    { input: "",                   desc: "empty string" },
+    { input: "hello world",       desc: "spaces" },
+    { input: "a\\nb",             desc: "backslash-n" },
+    { input: "a;echo INJECTED",   desc: "shell metacharacters" },
+    { input: 'both "and" it\'s',  desc: "single and double quotes" },
+    { input: "'",                  desc: "lone single quote" },
+    { input: "a'b'c'd",           desc: "multiple single quotes" },
+    { input: "$HOME",             desc: "dollar variable" },
+    { input: "`whoami`",          desc: "backtick command" },
+];
+
+async function runSuite(label, spawnFn, parseFn) {
+    var passed = 0;
+    var failed = 0;
+    console.log("--- " + label + " ---");
+    for (var i = 0; i < TEST_CASES.length; i++) {
+        var tc = TEST_CASES[i];
+        var parsed = parseFn(tc.input);
+        var r = await spawnFn(parsed);
+        var ok = r.received === tc.input;
+        if (ok) {
+            passed++;
+            console.log("  PASS  " + tc.desc);
+        } else {
+            failed++;
+            console.log("  FAIL  " + tc.desc);
+            console.log("        input:    " + JSON.stringify(tc.input));
+            console.log("        parsed:   " + JSON.stringify(parsed));
+            console.log("        received: " + JSON.stringify(r.received));
+            console.log("        exit:     " + r.exitCode);
+            if (r.stderr) console.log("        stderr:   " + r.stderr);
+        }
+    }
+    console.log("  " + passed + " passed, " + failed + " failed\n");
+    return failed;
+}
+
+async function main() {
+    console.log("parseTestString quoting regression test");
+    console.log("Platform: " + process.platform + ", Node: " + process.version);
+    console.log("Receiver: " + RECEIVER);
+    console.log("");
+
+    var totalFail = 0;
+
+    // Bash tests
+    try {
+        cp.execSync("bash --version", { stdio: "ignore" });
+        totalFail += await runSuite("Bash (actual shell)", spawnTestBash, parseTestString_bash);
+    } catch (_) {
+        console.log("--- Bash: SKIPPED (bash not available) ---\n");
+    }
+
+    // CMD tests (Windows only)
+    if (process.platform === "win32") {
+        totalFail += await runSuite("CMD (actual shell)", spawnTestCmd, parseTestString_cmd);
+    } else {
+        console.log("--- CMD: SKIPPED (not Windows) ---\n");
+    }
+
+    // PowerShell: note
+    console.log("--- PowerShell: NOT TESTED ---");
+    console.log("  (Requires ComSpec set to PowerShell; verify manually)\n");
+
+    if (totalFail > 0) {
+        console.log("RESULT: " + totalFail + " test(s) FAILED");
+        process.exit(1);
+    } else {
+        console.log("RESULT: All tests passed");
+    }
+}
+
+main().catch(function (e) { console.error(e); process.exit(1); });