diff --git a/deps.ts b/deps.ts
index a44f82a..9540ceb 100644
--- a/deps.ts
+++ b/deps.ts
@@ -33,11 +33,13 @@ export {
 
 export {
   blue,
+  brightBlack,
   gray,
   green,
   red,
   yellow,
 } from "https://deno.land/std@0.116.0/fmt/colors.ts";
+export { fromFileUrl } from "https://deno.land/std@0.116.0/path/mod.ts";
 
 // third party
 
diff --git a/report/README.md b/report/README.md
new file mode 100644
index 0000000..afcaef7
--- /dev/null
+++ b/report/README.md
@@ -0,0 +1,3 @@
+# report
+
+assert result reporter
diff --git a/report/assertion.ts b/report/assertion.ts
new file mode 100644
index 0000000..259b316
--- /dev/null
+++ b/report/assertion.ts
@@ -0,0 +1,35 @@
+// Copyright 2021-Present the Unitest authors. All rights reserved. MIT license.
+import { brightBlack, red } from "../deps.ts";
+
+type CodeInfo = {
+  code: string;
+  lineNumber: number;
+  column: number;
+};
+
+// /** insert something to beginning of line */
+// function BOL(text: string, symbol: string): string {
+//   return `${symbol}${text.replaceAll("\n", `\n${symbol}`)}`;
+// }
+
+function prettyCode({ code, lineNumber }: CodeInfo): string {
+  const codes = code.split("\n");
+
+  const sliced = codes.slice(
+    lineNumber - 2,
+    lineNumber + 2,
+  );
+
+  const numberedCodes = sliced.map((fragment, i) => {
+    const number = i + lineNumber - 1;
+    const isWrongLine = number === lineNumber;
+
+    return `${isWrongLine ? red(">") : " "}  ${brightBlack(String(number))} ${
+      brightBlack("|")
+    }  ${isWrongLine ? fragment : brightBlack(fragment)}`;
+  });
+
+  return numberedCodes.join("\n");
+}
+
+export { prettyCode };
diff --git a/report/stack_trace.ts b/report/stack_trace.ts
new file mode 100644
index 0000000..77cea2c
--- /dev/null
+++ b/report/stack_trace.ts
@@ -0,0 +1,33 @@
+// Copyright 2021-Present the Unitest authors. All rights reserved. MIT license.
+type StackTrace = {
+  file: string;
+  methodName: string;
+  lineNumber: number;
+  column: number;
+};
+
+function parseStackTraceLine(line: string): StackTrace | null {
+  const re =
+    /^\s*at (?<methodName>\S+) \(?(?<file>\S+):(?<lineNumber>\d+):(?<column>\d+)\)?.*$/i;
+
+  const result = re.exec(line);
+  if (!result || !result.groups) return null;
+  const { file, methodName, lineNumber, column } = result.groups;
+
+  return {
+    file,
+    methodName,
+    lineNumber: Number(lineNumber),
+    column: Number(column),
+  };
+}
+
+function parseStackTrace(stack: string): StackTrace[] {
+  const lines = stack.split("\n");
+
+  const traces = lines.map((line) => parseStackTraceLine(line));
+
+  return traces.filter(Boolean) as StackTrace[];
+}
+
+export { parseStackTrace, parseStackTraceLine };
diff --git a/report/stack_trace_test.ts b/report/stack_trace_test.ts
new file mode 100644
index 0000000..78158ac
--- /dev/null
+++ b/report/stack_trace_test.ts
@@ -0,0 +1,86 @@
+// Copyright 2021-Present the Unitest authors. All rights reserved. MIT license.
+import { assertEquals } from "../dev_deps.ts";
+import { parseStackTrace, parseStackTraceLine } from "./stack_trace.ts";
+
+Deno.test({
+  name: "parseStackTraceLine",
+  fn: () => {
+    const table: [
+      ...Parameters<typeof parseStackTraceLine>,
+      ReturnType<typeof parseStackTraceLine>,
+    ][] = [
+      [
+        `    at main (file:///path/to/file.ts:23:11)`,
+        {
+          file: "file:///path/to/file.ts",
+          methodName: "main",
+          lineNumber: 23,
+          column: 11,
+        },
+      ],
+      [
+        `    at assertEquals (https://deno.land/std@0.115.1/testing/asserts.ts:266:9)`,
+        {
+          file: "https://deno.land/std@0.115.1/testing/asserts.ts",
+          methodName: "assertEquals",
+          lineNumber: 266,
+          column: 9,
+        },
+      ],
+
+      [
+        `    at assertEquals https://deno.land/std@0.115.1/testing/asserts.ts:266:9`,
+        {
+          file: "https://deno.land/std@0.115.1/testing/asserts.ts",
+          methodName: "assertEquals",
+          lineNumber: 266,
+          column: 9,
+        },
+      ],
+
+      [
+        `    at Array.forEach (<anonymous>)`,
+        null,
+      ],
+    ];
+
+    table.forEach(([value, result]) => {
+      assertEquals(parseStackTraceLine(value), result);
+    });
+  },
+});
+
+Deno.test({
+  name: "trace",
+  fn: () => {
+    const table: [
+      ...Parameters<typeof parseStackTrace>,
+      ReturnType<typeof parseStackTrace>,
+    ][] = [
+      [
+        `ReferenceError: FAIL is not defined
+      at Constraint.execute (deltablue.js:525:2)
+      at Constraint.execute anonymous
+      at Constraint.recalculate (deltablue.js:424:21)`,
+        [
+          {
+            file: "deltablue.js",
+            methodName: "Constraint.execute",
+            lineNumber: 525,
+            column: 2,
+          },
+          {
+            file: "deltablue.js",
+            methodName: "Constraint.recalculate",
+            lineNumber: 424,
+            column: 21,
+          },
+        ],
+      ],
+    ];
+
+    table.forEach(([value, result]) => {
+      assertEquals(parseStackTrace(value), result);
+    });
+  },
+});
diff --git a/test/mod.ts b/test/mod.ts
index ce93afc..21e41c9 100644
--- a/test/mod.ts
+++ b/test/mod.ts
@@ -1,7 +1,9 @@
 // Copyright 2021-Present the Unitest authors. All rights reserved. MIT license.
 import { AnyFn } from "../_types.ts";
-import { isString } from "../deps.ts";
+import { AssertionError, fromFileUrl, isString } from "../deps.ts";
 import { each } from "./each.ts";
+import { parseStackTrace } from "../report/stack_trace.ts";
+import { prettyCode } from "../report/assertion.ts";
 
 type Test<Context extends Record<PropertyKey, unknown>> = {
   setup?: () => Context | void;
@@ -41,6 +43,37 @@ function _test<T extends Record<PropertyKey, unknown>>(
 
         try {
           await fn({ ...context, ...denoContext });
+        } catch (e) {
+          if (e instanceof Error) {
+            if (e.stack) {
+              const { state } = await Deno.permissions.query({
+                name: "read",
+              });
+
+              if (state !== "granted") {
+                throw e;
+              }
+
+              const stackTraces = parseStackTrace(e.stack);
+              const testFileStack = stackTraces.find(({ file }) => {
+                return /file:\/\/\S+_test\.[j|t]sx?$/.test(file);
+              });
+
+              if (!testFileStack) {
+                throw e;
+              }
+
+              const { lineNumber, column, file } = testFileStack;
+              const code = await Deno.readTextFile(
+                fromFileUrl(file),
+              );
+
+              const pretty = prettyCode({ code, lineNumber, column });
+              throw new AssertionError(`${e.message}\n${pretty}\n`);
+            }
+          } else {
+            throw Error("panic: unexpected error");
+          }
         } finally {
           teardown?.(context);
         }