diff --git a/src/language-tools/java.ts b/src/language-tools/java.ts
index b17ea05..eb48758 100644
--- a/src/language-tools/java.ts
+++ b/src/language-tools/java.ts
@@ -20,7 +20,10 @@ export class JavaLanguageTools implements LanguageTools {
    * @returns Lookup key to find this test case in the TestRunTracker.
    */
   mapTestFinishDataToLookupKey(testFinishData: TestFinish): string | undefined {
-    if (testFinishData.dataKind === TestFinishDataKind.JUnitStyleTestCaseData) {
+    if (
+      testFinishData.dataKind === TestFinishDataKind.JUnitStyleTestCaseData &&
+      testFinishData.data
+    ) {
       const testCaseData = testFinishData.data as JUnitStyleTestCaseData
       if (testCaseData.className !== undefined) {
         let testCaseName = testFinishData.displayName
@@ -31,7 +34,10 @@ export class JavaLanguageTools implements LanguageTools {
           testCaseName = match.groups.lookupKey
         }
 
-        return `${testCaseData.className}.${testCaseName}`
+        // Use the class name as the base, and append the test case name if available.
+        let result = testCaseData.className
+        if (testCaseName.length > 0) result += `.${testCaseName}`
+        return result
       } else {
         return testFinishData.displayName
       }
diff --git a/src/language-tools/python.ts b/src/language-tools/python.ts
index 2879bb5..f71feac 100644
--- a/src/language-tools/python.ts
+++ b/src/language-tools/python.ts
@@ -22,7 +22,10 @@ export class PythonLanguageTools
    * @returns Lookup key to find this test case in the TestRunTracker.
    */
   mapTestFinishDataToLookupKey(testFinishData: TestFinish): string | undefined {
-    if (testFinishData.dataKind === TestFinishDataKind.JUnitStyleTestCaseData) {
+    if (
+      testFinishData.dataKind === TestFinishDataKind.JUnitStyleTestCaseData &&
+      testFinishData.data
+    ) {
       const testCaseData = testFinishData.data as JUnitStyleTestCaseData
       let testCaseName = testFinishData.displayName
 
@@ -32,7 +35,10 @@ export class PythonLanguageTools
         testCaseName = match.groups.lookupKey
       }
 
-      return `${testCaseData.className}.${testCaseName}`
+      // Use the class name as the base, and append the test case name if available.
+      let result = testCaseData.className
+      if (testCaseName.length > 0) result += `.${testCaseName}`
+      return result
     }
     return undefined
   }
diff --git a/src/test/suite/language-tools/java.test.ts b/src/test/suite/language-tools/java.test.ts
index 524eb3c..1b29cb1 100644
--- a/src/test/suite/language-tools/java.test.ts
+++ b/src/test/suite/language-tools/java.test.ts
@@ -99,45 +99,149 @@ suite('Java Language Tools', () => {
     assert.strictEqual(result.testCases.length, 0)
   })
 
-  test('map test finish data to lookup key', async () => {
-    let result = languageTools.mapTestFinishDataToLookupKey({
-      displayName: 'myTest',
-      status: TestStatus.Failed,
-      dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
-      data: {
-        time: 0,
-        className: 'com.example.ClassName',
+  const testCases = [
+    {
+      description: 'test method within a class',
+      input: {
+        displayName: 'myTest',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'com.example.ClassName',
+        },
       },
-    })
-    assert.strictEqual(result, 'com.example.ClassName.myTest')
-
-    result = languageTools.mapTestFinishDataToLookupKey({
-      displayName: 'com.example.MySuite',
-      status: TestStatus.Failed,
-      dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
-      data: {
-        time: 0,
+      expected: 'com.example.ClassName.myTest',
+    },
+    {
+      description: 'suite level test case',
+      input: {
+        displayName: 'com.example.MySuite',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+        },
       },
-    })
-    assert.strictEqual(result, 'com.example.MySuite')
-
-    result = languageTools.mapTestFinishDataToLookupKey({
-      displayName: 'com.example.MySuite',
-      status: TestStatus.Failed,
-    })
-    assert.strictEqual(result, undefined)
-
-    result = languageTools.mapTestFinishDataToLookupKey({
-      displayName: 'myTest[example1]',
-      status: TestStatus.Failed,
-      dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
-      data: {
-        time: 0,
-        className: 'com.example.ClassName',
+      expected: 'com.example.MySuite',
+    },
+    {
+      description: 'no dataKind provided',
+      input: {
+        displayName: 'com.example.MySuite',
+        status: TestStatus.Failed,
+      },
+      expected: undefined,
+    },
+    {
+      description: 'parameterized test cases',
+      input: {
+        displayName: 'myTest[example1]',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'com.example.ClassName',
+        },
+      },
+      expected: 'com.example.ClassName.myTest',
+    },
+    {
+      description: 'successful tests with data',
+      input: {
+        displayName: 'mySuccessfulTest',
+        status: TestStatus.Passed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 1,
+          className: 'com.example.SuccessClass',
+        },
       },
+      expected: 'com.example.SuccessClass.mySuccessfulTest',
+    },
+    {
+      description: 'tests with no className',
+      input: {
+        displayName: 'myTestWithoutClass',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 2,
+        },
+      },
+      expected: 'myTestWithoutClass',
+    },
+    {
+      description: 'unknown dataKind',
+      input: {
+        displayName: 'unknownTest',
+        status: TestStatus.Failed,
+        dataKind: 'UnknownDataKind',
+        data: {
+          time: 0,
+          className: 'com.example.UnknownClass',
+        },
+      },
+      expected: undefined,
+    },
+    // Remaining scenarios are unexpected, but should still return results.
+    {
+      description: 'null data gracefully',
+      input: {
+        displayName: 'nullDataTest',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: null,
+      },
+      expected: undefined,
+    },
+    {
+      description: 'numeric displayName',
+      input: {
+        displayName: '123456',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'com.example.ClassName',
+        },
+      },
+      expected: 'com.example.ClassName.123456',
+    },
+    {
+      description: 'special characters in displayName',
+      input: {
+        displayName: '!@#$%^&*()',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'com.example.ClassName',
+        },
+      },
+      expected: 'com.example.ClassName.!@#$%^&*()',
+    },
+    {
+      description: 'empty string as displayName',
+      input: {
+        displayName: '',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'com.example.ClassName',
+        },
+      },
+      expected: 'com.example.ClassName',
+    },
+  ]
+
+  for (const testCase of testCases) {
+    test(`map test finish data to lookup key: ${testCase.description}`, async () => {
+      const result = languageTools.mapTestFinishDataToLookupKey(testCase.input)
+      assert.strictEqual(result, testCase.expected)
     })
-    assert.strictEqual(result, 'com.example.ClassName.myTest')
-  })
+  }
 
   test('map test case info to lookup key', async () => {
     let testInfo = testController.createTestItem('test1', 'test1')
diff --git a/src/test/suite/language-tools/python.test.ts b/src/test/suite/language-tools/python.test.ts
index f025c7d..3c4cc9d 100644
--- a/src/test/suite/language-tools/python.test.ts
+++ b/src/test/suite/language-tools/python.test.ts
@@ -88,49 +88,139 @@ suite('Python Language Tools', () => {
     assert.ok(executeCommandStub.notCalled)
   })
 
-  test('map test finish data to lookup key', async () => {
-    let result = languageTools.mapTestFinishDataToLookupKey({
-      displayName: 'test_method',
-      status: TestStatus.Failed,
-      dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
-      data: {
-        time: 0,
-        className: 'my.example.test_example.TestMyClass',
+  const testCases = [
+    {
+      description: 'method within a class',
+      input: {
+        displayName: 'test_method',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'my.example.test_example.TestMyClass',
+        },
       },
-    })
-    assert.strictEqual(
-      result,
-      'my.example.test_example.TestMyClass.test_method'
-    )
-
-    result = languageTools.mapTestFinishDataToLookupKey({
-      displayName: 'test_method',
-      status: TestStatus.Failed,
-      dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
-      data: {
-        time: 0,
-        className: 'my.example.test_example',
+      expected: 'my.example.test_example.TestMyClass.test_method',
+    },
+    {
+      description: 'standalone method',
+      input: {
+        displayName: 'test_method',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'my.example.test_example',
+        },
       },
-    })
-    assert.strictEqual(result, 'my.example.test_example.test_method')
-
-    result = languageTools.mapTestFinishDataToLookupKey({
-      displayName: 'test_method[example1]',
-      status: TestStatus.Failed,
-      dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
-      data: {
-        time: 0,
-        className: 'my.example.test_example',
+      expected: 'my.example.test_example.test_method',
+    },
+    {
+      description: 'parameterized test result',
+      input: {
+        displayName: 'test_method[example1]',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'my.example.test_example',
+        },
       },
-    })
-    assert.strictEqual(result, 'my.example.test_example.test_method')
+      expected: 'my.example.test_example.test_method',
+    },
+    {
+      description: 'result with no data',
+      input: {
+        displayName: 'pytest',
+        status: TestStatus.Failed,
+      },
+      expected: undefined,
+    },
+    {
+      description: 'successful test case',
+      input: {
+        displayName: 'test_successful_method',
+        status: TestStatus.Passed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 1,
+          className: 'my.example.test_example.TestMyClass',
+        },
+      },
+      expected: 'my.example.test_example.TestMyClass.test_successful_method',
+    },
+    {
+      description: 'unknown dataKind',
+      input: {
+        displayName: 'unknown_test',
+        status: TestStatus.Failed,
+        dataKind: 'UnknownDataKind',
+        data: {
+          time: 0,
+          className: 'my.example.test_example.UnknownClass',
+        },
+      },
+      expected: undefined,
+    },
+    // Remaining scenarios are unexpected, but should still return results.
+    {
+      description: 'method with special characters',
+      input: {
+        displayName: 'test_method_with_special_chars!@#',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'my.example.test_example.TestMyClass',
+        },
+      },
+      expected:
+        'my.example.test_example.TestMyClass.test_method_with_special_chars!@#',
+    },
+    {
+      description: 'method with numeric displayName',
+      input: {
+        displayName: '123456',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'my.example.test_example.TestMyClass',
+        },
+      },
+      expected: 'my.example.test_example.TestMyClass.123456',
+    },
+    {
+      description: 'empty string as displayName',
+      input: {
+        displayName: '',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: {
+          time: 0,
+          className: 'my.example.test_example.TestMyClass',
+        },
+      },
+      expected: 'my.example.test_example.TestMyClass',
+    },
+    {
+      description: 'null data gracefully',
+      input: {
+        displayName: 'null_data_test',
+        status: TestStatus.Failed,
+        dataKind: TestFinishDataKind.JUnitStyleTestCaseData,
+        data: null,
+      },
+      expected: undefined,
+    },
+  ]
 
-    result = languageTools.mapTestFinishDataToLookupKey({
-      displayName: 'pytest',
-      status: TestStatus.Failed,
+  for (const testCase of testCases) {
+    test(`map test finish data to lookup key: ${testCase.description}`, async () => {
+      const result = languageTools.mapTestFinishDataToLookupKey(testCase.input)
+      assert.strictEqual(result, testCase.expected)
     })
-    assert.strictEqual(result, undefined)
-  })
+  }
 
   test('map test case info to lookup key', async () => {
     let testInfo = testController.createTestItem('test1', 'test1')