feat: Record test failure details in mocha

Fixes #231

components/recorder-cli/mocha/index.mjs

@@ -1,6 +1,9 @@
 import process from "node:process";
 import { hooks } from "../../../lib/node/mocha-hook.mjs";
-import { ExternalAppmapError } from "../../error/index.mjs";
+import {
+  ExternalAppmapError,
+  parseExceptionStack,
+} from "../../error/index.mjs";
 import { logInfo, logErrorWhen } from "../../log/index.mjs";
 import { getUuid } from "../../uuid/index.mjs";
 import { extendConfiguration } from "../../configuration/index.mjs";
@@ -26,8 +29,24 @@ import {
   closeSocket,
   addSocketListener,
 } from "../../socket/index.mjs";
+import { stringifyLocation } from "../../location/index.mjs";
+
+const { undefined, parseInt, Boolean, Promise } = globalThis;
 
-const { undefined, parseInt, Promise } = globalThis;
+const buildTestFailure = (error) => {
+  if (!error?.name) {
+    return undefined;
+  }
+  const message = [error.name, error.message].filter(Boolean).join(": ");
+  const frame = parseExceptionStack(error)?.at(0);
+  if (!frame) {
+    return { message };
+  }
+  return {
+    message,
+    location: stringifyLocation({ position: frame, url: frame.fileName }),
+  };
+};
 
 // Accessing mocha version via the prototype is not documented but it seems stable enough.
 // Added in https://github.com/mochajs/mocha/pull/3535
@@ -140,9 +159,11 @@ export const recordAsync = (configuration) => {
       "No running mocha test case",
       ExternalAppmapError,
     );
+    const passed = context.currentTest.state === "passed";
     recordStopTrack(frontend, running.track, {
       type: "test",
-      passed: context.currentTest.state === "passed",
+      passed,
+      failure: passed ? undefined : buildTestFailure(context.currentTest.err),
     });
     flush();
     running = null;

components/recorder-cli/mocha/index.test.mjs

@@ -10,7 +10,7 @@ import {
 } from "../../configuration/index.mjs";
 import { recordAsync } from "./index.mjs";
 
-const { setImmediate } = globalThis;
+const { Error, setImmediate, undefined } = globalThis;
 
 const getLastMockSocket = readGlobal("GET_LAST_MOCK_SOCKET");
 const receiveMockSocket = readGlobal("RECEIVE_MOCK_SOCKET");
@@ -45,18 +45,48 @@ setImmediate(() => {
   receiveMockSocket(getLastMockSocket(), "0");
 });
 
-await beforeEach.call({
-  currentTest: {
-    parent: {
-      fullTitle: () => "full-title-1",
+const startTest = () =>
+  beforeEach.call({
+    currentTest: {
+      parent: {
+        fullTitle: () => "full-title-1",
+      },
     },
+  });
+
+await startTest();
+
+await afterEach.call({
+  currentTest: {
+    state: "passed",
   },
 });
 
+await startTest();
+
 await afterEach.call({
   currentTest: {
-    state: "passed",
+    state: "failed",
+    err: new Error("test error"),
   },
 });
 
 await afterAll();
+
+const testFailure = async (error) => {
+  await startTest();
+  return afterEach.call({
+    currentTest: {
+      state: "failed",
+      err: error,
+    },
+  });
+};
+
+await testFailure(undefined);
+await testFailure({ name: "TestError", message: "test error" });
+await testFailure({
+  name: "TestError",
+  message: "test error",
+  stack: "TestError: test error\n  at /app/foo-bar.js:4:6",
+});

components/trace/appmap/index.mjs

@@ -9,6 +9,7 @@ import {
   logInfo,
   logInfoWhen,
 } from "../../log/index.mjs";
+import { toRelativeUrl } from "../../url/index.mjs";
 import { validateAppmap } from "../../validate-appmap/index.mjs";
 import { parseLocation } from "../../location/index.mjs";
 import {
@@ -22,11 +23,13 @@ import { orderEventArray } from "./ordering/index.mjs";
 import { getOutputUrl } from "./output.mjs";
 
 const {
+  Boolean,
   Map,
   Array: { from: toArray },
   String,
   Math: { round },
   RangeError,
+  URL,
 } = globalThis;
 
 const VERSION = "1.8.0";
@@ -181,6 +184,18 @@ const printApplyEventDistribution = (events, codebase) => {
     .join("");
 };
 
+const makeFailure = ({ message, location }, { base }) => {
+  if (!location) {
+    return { message };
+  }
+  const {
+    url,
+    position: { line },
+  } = parseLocation(location);
+  const relative = toRelativeUrl(new URL(url, base), base);
+  return { message, location: [relative, line].filter(Boolean).join(":") };
+};
+
 export const compileTrace = (configuration, files, messages, termination) => {
   logDebug("Trace: %j", { configuration, files, messages, termination });
   const errors = [];
@@ -290,12 +305,18 @@ export const compileTrace = (configuration, files, messages, termination) => {
     }
   }
   /* c8 ignore stop */
+
   const appmap = {
     version: VERSION,
     metadata: compileMetadata(configuration, errors, termination),
     classMap: exportClassmap(codebase),
     events: digested_events,
   };
+
+  if (termination.failure) {
+    appmap.metadata.test_failure = makeFailure(termination.failure, codebase);
+  }
+
   if (configuration.validate.appmap) {
     validateAppmap(appmap);
   }