diff --git a/src/client/testing/testController/common/resultResolver.ts b/src/client/testing/testController/common/resultResolver.ts
index 78883bdcf8fb..79cee6452a8c 100644
--- a/src/client/testing/testController/common/resultResolver.ts
+++ b/src/client/testing/testController/common/resultResolver.ts
@@ -11,7 +11,7 @@ import { clearAllChildren, createErrorTestItem, getTestCaseNodes } from './testI
 import { sendTelemetryEvent } from '../../../telemetry';
 import { EventName } from '../../../telemetry/constants';
 import { splitLines } from '../../../common/stringUtils';
-import { buildErrorNodeOptions, fixLogLines, populateTestTree } from './utils';
+import { buildErrorNodeOptions, fixLogLines, populateTestTree, splitTestNameWithRegex } from './utils';
 import { Deferred } from '../../../common/utils/async';
 
 export class PythonResultResolver implements ITestResultResolver {
@@ -216,9 +216,8 @@ export class PythonResultResolver implements ITestResultResolver {
                         });
                     }
                 } else if (rawTestExecData.result[keyTemp].outcome === 'subtest-failure') {
-                    // split on " " since the subtest ID has the parent test ID in the first part of the ID.
-                    const parentTestCaseId = keyTemp.split(' ')[0];
-                    const subtestId = keyTemp.split(' ')[1];
+                    // split on [] or () based on how the subtest is setup.
+                    const [parentTestCaseId, subtestId] = splitTestNameWithRegex(keyTemp);
                     const parentTestItem = this.runIdToTestItem.get(parentTestCaseId);
                     const data = rawTestExecData.result[keyTemp];
                     // find the subtest's parent test item
@@ -227,7 +226,10 @@ export class PythonResultResolver implements ITestResultResolver {
                         if (subtestStats) {
                             subtestStats.failed += 1;
                         } else {
-                            this.subTestStats.set(parentTestCaseId, { failed: 1, passed: 0 });
+                            this.subTestStats.set(parentTestCaseId, {
+                                failed: 1,
+                                passed: 0,
+                            });
                             runInstance.appendOutput(fixLogLines(`${parentTestCaseId} [subtests]:\r\n`));
                             // clear since subtest items don't persist between runs
                             clearAllChildren(parentTestItem);
@@ -253,11 +255,8 @@ export class PythonResultResolver implements ITestResultResolver {
                         throw new Error('Parent test item not found');
                     }
                 } else if (rawTestExecData.result[keyTemp].outcome === 'subtest-success') {
-                    // split only on first " [" since the subtest ID has the parent test ID in the first part of the ID.
-                    const index = keyTemp.indexOf(' [');
-                    const parentTestCaseId = keyTemp.substring(0, index);
-                    // add one to index to remove the space from the start of the subtest ID
-                    const subtestId = keyTemp.substring(index + 1, keyTemp.length);
+                    // split on [] or () based on how the subtest is setup.
+                    const [parentTestCaseId, subtestId] = splitTestNameWithRegex(keyTemp);
                     const parentTestItem = this.runIdToTestItem.get(parentTestCaseId);
 
                     // find the subtest's parent test item
diff --git a/src/client/testing/testController/common/utils.ts b/src/client/testing/testController/common/utils.ts
index 1272ff37fb5d..4a0c7078667a 100644
--- a/src/client/testing/testController/common/utils.ts
+++ b/src/client/testing/testController/common/utils.ts
@@ -320,3 +320,28 @@ export function createEOTPayload(executionBool: boolean): EOTTestPayload {
         eot: true,
     } as EOTTestPayload;
 }
+
+/**
+ * Splits a test name into its parent test name and subtest unique section.
+ *
+ * @param testName The full test name string.
+ * @returns A tuple where the first item is the parent test name and the second item is the subtest section or `testName` if no subtest section exists.
+ */
+export function splitTestNameWithRegex(testName: string): [string, string] {
+    // The regex pattern has three main components:
+    // 1. ^(.*?): Matches the beginning of the string and captures everything until the last opening bracket or parenthesis. This captures the parent test name.
+    // 2. (?:...|...): A non-capturing group containing two patterns separated by an OR (|).
+    //    - \(([^)]+)\): Matches an opening parenthesis, captures everything inside it until the closing parenthesis. This captures the subtest inside parenthesis.
+    //    - \[([^]]+)\]: Matches an opening square bracket, captures everything inside it until the closing square bracket. This captures the subtest inside square brackets.
+    // 3. ?$: The question mark indicates the preceding non-capturing group is optional. The dollar sign matches the end of the string.
+    const regex = /^(.*?) ([\[(].*[\])])$/;
+    const match = testName.match(regex);
+    // const m2 = regex.exec(testName);
+    // console.log('m2', m2);
+    // If a match is found, return the parent test name and the subtest (whichever was captured between parenthesis or square brackets).
+    // Otherwise, return the entire testName for the parent and entire testName for the subtest.
+    if (match) {
+        return [match[1].trim(), match[2] || match[3] || testName];
+    }
+    return [testName, testName];
+}
diff --git a/src/test/testing/testController/utils.unit.test.ts b/src/test/testing/testController/utils.unit.test.ts
index 9168abc7041f..12100252d1a9 100644
--- a/src/test/testing/testController/utils.unit.test.ts
+++ b/src/test/testing/testController/utils.unit.test.ts
@@ -8,6 +8,7 @@ import {
     JSONRPC_UUID_HEADER,
     ExtractJsonRPCData,
     parseJsonRPCHeadersAndData,
+    splitTestNameWithRegex,
 } from '../../../client/testing/testController/common/utils';
 
 suite('Test Controller Utils: JSON RPC', () => {
@@ -65,3 +66,58 @@ suite('Test Controller Utils: JSON RPC', () => {
         assert.deepStrictEqual(rpcContent.remainingRawData, rawDataString);
     });
 });
+
+suite('Test Controller Utils: Other', () => {
+    interface TestCase {
+        name: string;
+        input: string;
+        expectedParent: string;
+        expectedSubtest: string;
+    }
+
+    const testCases: Array<TestCase> = [
+        {
+            name: 'Single parameter, named',
+            input: 'test_package.ClassName.test_method (param=value)',
+            expectedParent: 'test_package.ClassName.test_method',
+            expectedSubtest: '(param=value)',
+        },
+        {
+            name: 'Single parameter, unnamed',
+            input: 'test_package.ClassName.test_method [value]',
+            expectedParent: 'test_package.ClassName.test_method',
+            expectedSubtest: '[value]',
+        },
+        {
+            name: 'Multiple parameters, named',
+            input: 'test_package.ClassName.test_method (param1=value1, param2=value2)',
+            expectedParent: 'test_package.ClassName.test_method',
+            expectedSubtest: '(param1=value1, param2=value2)',
+        },
+        {
+            name: 'Multiple parameters, unnamed',
+            input: 'test_package.ClassName.test_method [value1, value2]',
+            expectedParent: 'test_package.ClassName.test_method',
+            expectedSubtest: '[value1, value2]',
+        },
+        {
+            name: 'Names with special characters',
+            input: 'test_package.ClassName.test_method (param1=value/1, param2=value+2)',
+            expectedParent: 'test_package.ClassName.test_method',
+            expectedSubtest: '(param1=value/1, param2=value+2)',
+        },
+        {
+            name: 'Names with spaces',
+            input: 'test_package.ClassName.test_method ["a b c d"]',
+            expectedParent: 'test_package.ClassName.test_method',
+            expectedSubtest: '["a b c d"]',
+        },
+    ];
+
+    testCases.forEach((testCase) => {
+        test(`splitTestNameWithRegex: ${testCase.name}`, () => {
+            const splitResult = splitTestNameWithRegex(testCase.input);
+            assert.deepStrictEqual(splitResult, [testCase.expectedParent, testCase.expectedSubtest]);
+        });
+    });
+});