diff --git a/fixtures/cli-preprocessor/index.js b/fixtures/cli-preprocessor/index.js
new file mode 100644
index 000000000..85e2454e5
--- /dev/null
+++ b/fixtures/cli-preprocessor/index.js
@@ -0,0 +1,4 @@
+export default function (options) {
+  console.log('hi from js preprocessor');
+  return options;
+}
diff --git a/fixtures/cli-preprocessor/index.ts b/fixtures/cli-preprocessor/index.ts
new file mode 100644
index 000000000..73487f28a
--- /dev/null
+++ b/fixtures/cli-preprocessor/index.ts
@@ -0,0 +1,4 @@
+export default function (options) {
+  console.log('hi from ts preprocessor');
+  return options;
+}
diff --git a/fixtures/cli-preprocessor/node_modules/@org/preprocessor/index.js b/fixtures/cli-preprocessor/node_modules/@org/preprocessor/index.js
new file mode 100644
index 000000000..2de00cde0
--- /dev/null
+++ b/fixtures/cli-preprocessor/node_modules/@org/preprocessor/index.js
@@ -0,0 +1,4 @@
+export default function (options) {
+  console.log('hi from scoped preprocessor');
+  return options;
+}
diff --git a/fixtures/cli-preprocessor/node_modules/@org/preprocessor/package.json b/fixtures/cli-preprocessor/node_modules/@org/preprocessor/package.json
new file mode 100644
index 000000000..c98c1fffa
--- /dev/null
+++ b/fixtures/cli-preprocessor/node_modules/@org/preprocessor/package.json
@@ -0,0 +1,4 @@
+{
+  "name": "@org/preprocessor",
+  "type": "module"
+}
diff --git a/fixtures/cli-preprocessor/node_modules/knip-preprocessor/index.js b/fixtures/cli-preprocessor/node_modules/knip-preprocessor/index.js
new file mode 100644
index 000000000..7d49738be
--- /dev/null
+++ b/fixtures/cli-preprocessor/node_modules/knip-preprocessor/index.js
@@ -0,0 +1,4 @@
+module.exports = function (options) {
+  console.log('hi from pkg preprocessor');
+  return options;
+};
diff --git a/fixtures/cli-preprocessor/node_modules/knip-preprocessor/package.json b/fixtures/cli-preprocessor/node_modules/knip-preprocessor/package.json
new file mode 100644
index 000000000..fcb515122
--- /dev/null
+++ b/fixtures/cli-preprocessor/node_modules/knip-preprocessor/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "knip-preprocessor"
+}
diff --git a/fixtures/cli-preprocessor/package.json b/fixtures/cli-preprocessor/package.json
new file mode 100644
index 000000000..3a72b1354
--- /dev/null
+++ b/fixtures/cli-preprocessor/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "@fixtures/cli-preprocessor"
+}
diff --git a/fixtures/cli-reporter/index.js b/fixtures/cli-reporter/index.js
new file mode 100644
index 000000000..c6192d180
--- /dev/null
+++ b/fixtures/cli-reporter/index.js
@@ -0,0 +1,3 @@
+export default function () {
+  console.log('hi from js reporter');
+}
diff --git a/fixtures/cli-reporter/index.ts b/fixtures/cli-reporter/index.ts
new file mode 100644
index 000000000..4d4a00ba4
--- /dev/null
+++ b/fixtures/cli-reporter/index.ts
@@ -0,0 +1,3 @@
+export default function () {
+  console.log('hi from ts reporter');
+}
diff --git a/fixtures/cli-reporter/node_modules/@org/reporter/index.js b/fixtures/cli-reporter/node_modules/@org/reporter/index.js
new file mode 100644
index 000000000..3ba3bb40f
--- /dev/null
+++ b/fixtures/cli-reporter/node_modules/@org/reporter/index.js
@@ -0,0 +1,3 @@
+export default function () {
+  console.log('hi from scoped reporter');
+}
diff --git a/fixtures/cli-reporter/node_modules/@org/reporter/package.json b/fixtures/cli-reporter/node_modules/@org/reporter/package.json
new file mode 100644
index 000000000..870b26ae5
--- /dev/null
+++ b/fixtures/cli-reporter/node_modules/@org/reporter/package.json
@@ -0,0 +1,4 @@
+{
+  "name": "@org/reporter",
+  "type": "module"
+}
diff --git a/fixtures/cli-reporter/node_modules/knip-reporter/index.js b/fixtures/cli-reporter/node_modules/knip-reporter/index.js
new file mode 100644
index 000000000..dd676cdab
--- /dev/null
+++ b/fixtures/cli-reporter/node_modules/knip-reporter/index.js
@@ -0,0 +1,3 @@
+module.exports = function () {
+  console.log('hi from pkg reporter');
+};
diff --git a/fixtures/cli-reporter/node_modules/knip-reporter/package.json b/fixtures/cli-reporter/node_modules/knip-reporter/package.json
new file mode 100644
index 000000000..3f701e222
--- /dev/null
+++ b/fixtures/cli-reporter/node_modules/knip-reporter/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "knip-reporter"
+}
diff --git a/fixtures/cli-reporter/package.json b/fixtures/cli-reporter/package.json
new file mode 100644
index 000000000..7eab78373
--- /dev/null
+++ b/fixtures/cli-reporter/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "@fixtures/cli-reporter"
+}
diff --git a/fixtures/cli/package.json b/fixtures/cli/package.json
new file mode 100644
index 000000000..1a0994fc4
--- /dev/null
+++ b/fixtures/cli/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "@fixtures/cli"
+}
diff --git a/tests/cli-preprocessor.test.ts b/tests/cli-preprocessor.test.ts
new file mode 100644
index 000000000..11d5ca76f
--- /dev/null
+++ b/tests/cli-preprocessor.test.ts
@@ -0,0 +1,27 @@
+import assert from 'node:assert/strict';
+import { execSync } from 'node:child_process';
+import test from 'node:test';
+import { resolve } from '../src/util/path.js';
+
+const cwd = resolve('fixtures/cli-preprocessor');
+
+const exec = (command: string) => {
+  const output = execSync(command.replace(/^knip/, 'node ../../dist/cli.js'), { cwd });
+  return output.toString().trim();
+};
+
+test('knip --preprocessor ./index.js', () => {
+  assert.equal(exec('knip --preprocessor ./index.js'), 'hi from js preprocessor');
+});
+
+test('knip --preprocessor ./index.ts', () => {
+  assert.equal(exec('knip --preprocessor ./index.ts'), 'hi from ts preprocessor');
+});
+
+test('knip --preprocessor knip-preprocessor', () => {
+  assert.equal(exec('knip --preprocessor knip-preprocessor'), 'hi from pkg preprocessor');
+});
+
+test('knip --preprocessor @org/preprocessor', () => {
+  assert.equal(exec('knip --preprocessor @org/preprocessor'), 'hi from scoped preprocessor');
+});
diff --git a/tests/cli-reporter.test.ts b/tests/cli-reporter.test.ts
new file mode 100644
index 000000000..47351e11d
--- /dev/null
+++ b/tests/cli-reporter.test.ts
@@ -0,0 +1,27 @@
+import assert from 'node:assert/strict';
+import { execSync } from 'node:child_process';
+import test from 'node:test';
+import { resolve } from '../src/util/path.js';
+
+const cwd = resolve('fixtures/cli-reporter');
+
+const exec = (command: string) => {
+  const output = execSync(command.replace(/^knip/, 'node ../../dist/cli.js'), { cwd });
+  return output.toString().trim();
+};
+
+test('knip --reporter ./index.js', () => {
+  assert.equal(exec('knip --reporter ./index.js'), 'hi from js reporter');
+});
+
+test('knip --reporter ./index.ts', () => {
+  assert.equal(exec('knip --reporter ./index.ts'), 'hi from ts reporter');
+});
+
+test('knip --reporter knip-reporter', () => {
+  assert.equal(exec('knip --reporter knip-reporter'), 'hi from pkg reporter');
+});
+
+test('knip --reporter @org/reporter', () => {
+  assert.equal(exec('knip --reporter @org/reporter'), 'hi from scoped reporter');
+});
diff --git a/tests/cli.test.ts b/tests/cli.test.ts
index da18a615f..49b19f89f 100644
--- a/tests/cli.test.ts
+++ b/tests/cli.test.ts
@@ -2,10 +2,13 @@ import assert from 'node:assert/strict';
 import { execSync } from 'node:child_process';
 import test from 'node:test';
 import { helpText } from '../src/util/cli-arguments.js';
+import { resolve } from '../src/util/path.js';
 import { version } from '../src/version.js';
 
+const cwd = resolve('fixtures/cli');
+
 const exec = (command: string) => {
-  const output = execSync(command.replace(/^knip/, 'node --no-warnings --loader tsx src/cli.ts'));
+  const output = execSync(command.replace(/^knip/, 'node ../../dist/cli.js'), { cwd });
   return output.toString().trim();
 };
 
@@ -16,7 +19,3 @@ test('knip --version', () => {
 test('knip --help', () => {
   assert.equal(exec('knip --help'), helpText);
 });
-
-test('knip', { skip: true }, () => {
-  assert.equal(exec('knip'), '✂️  Excellent, Knip found no issues.');
-});