diff --git a/parse-report.js b/parse-report.js
index ed4a51a..8067b72 100644
--- a/parse-report.js
+++ b/parse-report.js
@@ -12,20 +12,26 @@ const durationRegex = /duration_ms\s([\d.]+)/
 export default async function parseReport(source) {
   const tests = []
   const testStack = []
-
-  let diagnosticMessage = ''
+  const allTests = Object.create(null)
+  let currentTest
   let totalDuration = 0
 
   function lastTestInStack() {
     return testStack.length ? testStack[testStack.length - 1] : null
   }
 
-  function appendDiagnosticMessage(message) {
-    diagnosticMessage += `${message}\n`
+  function appendDiagnosticMessage(data) {
+    // currentTest is for diagnostics after all tests are complete
+    // which do not have a file, line, or column.
+    const t = allTests[testId(data)] || currentTest
+    if (!t.diagnostic) {
+      t.diagnostic = ''
+    }
+    t.diagnostic += `${data.message}\n`
   }
 
-  function resetDiagnosticMessage() {
-    diagnosticMessage = ''
+  function testId(data) {
+    return [data.file, data.line, data.column].join('\0')
   }
 
   function isFileUrl(urlString) {
@@ -52,13 +58,13 @@ export default async function parseReport(source) {
           data: { name, file }
         } = event
 
-        resetDiagnosticMessage()
-
-        testStack.push({
+        const t = {
           name,
           file: parseFilePath(file),
           tests: []
-        })
+        }
+        allTests[testId(event.data)] = t
+        testStack.push(t)
 
         break
 
@@ -72,7 +78,7 @@ export default async function parseReport(source) {
           }
         } = event
 
-        const currentTest = testStack.pop()
+        currentTest = testStack.pop()
         currentTest.duration = duration
         currentTest.skip = skip !== undefined
         currentTest.todo = todo !== undefined
@@ -89,10 +95,6 @@ export default async function parseReport(source) {
           }
         }
 
-        if (diagnosticMessage) {
-          currentTest.diagnostic = diagnosticMessage
-        }
-
         if (lastTestInStack()) {
           lastTestInStack().tests.push(currentTest)
         } else {
@@ -111,7 +113,7 @@ export default async function parseReport(source) {
           totalDuration = parseFloat(durationMatch[1])
         }
 
-        appendDiagnosticMessage(message)
+        appendDiagnosticMessage(event.data)
 
         break
     }
diff --git a/test/e2e/compare.sh b/test/e2e/compare.sh
index c59d394..4f1ddf7 100755
--- a/test/e2e/compare.sh
+++ b/test/e2e/compare.sh
@@ -3,7 +3,7 @@ set -e
 
 # Function to replace test duration with 0 and remove file paths
 remove_variables() {
-  echo "$1" | sed -E 's/\"duration\": [0-9.]+/\"duration\": 0/g' | sed -E 's/\/.*\/test\//test\//g' | sed -E 's/("operator": "strictEqual"),/\1/g' | sed -E '/ *"diff": "simple"/d'
+  echo "$1" | sed -E 's/\"duration\": [0-9.]+/\"duration\": 0/g' | sed -E 's/\/.*\/test\//test\//g' | sed -E 's/("operator": "strictEqual"),/\1/g' | sed -E '/ *"diff": "simple"/d' | sed -E 's/duration_ms [0-9.]+/duration_ms 0/g'
 }
 
 # Run sample tests and generate the report, ignoring errors
diff --git a/test/resources/expected.json b/test/resources/expected.json
index 821daf5..1c3684e 100644
--- a/test/resources/expected.json
+++ b/test/resources/expected.json
@@ -31,7 +31,8 @@
                   "tests": [],
                   "duration": 0,
                   "skip": false,
-                  "todo": false
+                  "todo": false,
+                  "diagnostic": "JJJJAJAJSDADS\n"
                 },
                 {
                   "name": "fails",
@@ -50,7 +51,8 @@
                       "expected": 2,
                       "operator": "strictEqual"
                     }
-                  }
+                  },
+                  "diagnostic": "IIIIOASDASD\n"
                 }
               ],
               "duration": 0,
@@ -127,8 +129,9 @@
       ],
       "duration": 0,
       "skip": false,
-      "todo": true
+      "todo": true,
+      "diagnostic": "tests 6\nsuites 5\npass 2\nfail 2\ncancelled 1\nskipped 1\ntodo 0\nduration_ms 0\n"
     }
   ],
   "duration": 0
-}
+}
\ No newline at end of file
diff --git a/test/resources/sample-tests/nested.test.js b/test/resources/sample-tests/nested.test.js
index 186046b..99a6ff0 100644
--- a/test/resources/sample-tests/nested.test.js
+++ b/test/resources/sample-tests/nested.test.js
@@ -4,11 +4,13 @@ import { describe, it } from 'node:test'
 describe('module', () => {
   describe('function', () => {
     describe('behavior', () => {
-      it('asserts 1 === 1', () => {
+      it('asserts 1 === 1', t => {
+        t.diagnostic('JJJJAJAJSDADS')
         assert.strictEqual(1, 1)
       })
 
-      it('fails', () => {
+      it('fails', t => {
+        t.diagnostic('IIIIOASDASD')
         assert.strictEqual(1, 2)
       })
     })