diff --git a/lib/kill.js b/lib/kill.js
index c23d6a5ad..dc1c77c38 100644
--- a/lib/kill.js
+++ b/lib/kill.js
@@ -85,7 +85,7 @@ const setupTimeout = (spawned, {timeout, killSignal = 'SIGTERM'}, spawnedPromise
 // `cleanup` option handling
 const setExitHandler = (spawned, {cleanup, detached}, timedPromise) => {
 	if (!cleanup || detached) {
-		return;
+		return timedPromise;
 	}
 
 	const removeExitHandler = onExit(() => {
diff --git a/test/fixtures/sub-process-exit b/test/fixtures/sub-process-exit
index 2b350a2b6..ea05f0e2d 100755
--- a/test/fixtures/sub-process-exit
+++ b/test/fixtures/sub-process-exit
@@ -4,4 +4,14 @@ const execa = require('../..');
 
 const cleanup = process.argv[2] === 'true';
 const detached = process.argv[3] === 'true';
-execa('node', ['./test/fixtures/noop'], {cleanup, detached});
+
+const runChild = async () => {
+	try {
+		await execa('node', ['./test/fixtures/noop'], {cleanup, detached});
+	} catch (error) {
+		console.error(error);
+		process.exit(1);
+	}
+};
+
+runChild();
diff --git a/test/stream.js b/test/stream.js
index fc388ad9f..c0f8ba7eb 100644
--- a/test/stream.js
+++ b/test/stream.js
@@ -172,15 +172,18 @@ test('buffer: false > promise rejects when process returns non-zero', async t =>
 
 const BUFFER_TIMEOUT = 1e3;
 
-test.serial('buffer: false > promise does not resolve when output is big and is not read', async t => {
-	const {timedOut} = await t.throwsAsync(execa('max-buffer', {buffer: false, timeout: BUFFER_TIMEOUT}));
-	t.true(timedOut);
-});
+// On Unix (not Windows), a process won't exit if stdout has not been read.
+if (process.platform !== 'win32') {
+	test.serial('buffer: false > promise does not resolve when output is big and is not read', async t => {
+		const {timedOut} = await t.throwsAsync(execa('max-buffer', {buffer: false, timeout: BUFFER_TIMEOUT}));
+		t.true(timedOut);
+	});
 
-test.serial('buffer: false > promise does not resolve when output is big and "all" is used but not read', async t => {
-	const cp = execa('max-buffer', {buffer: false, all: true, timeout: BUFFER_TIMEOUT});
-	cp.stdout.resume();
-	cp.stderr.resume();
-	const {timedOut} = await t.throwsAsync(cp);
-	t.true(timedOut);
-});
+	test.serial('buffer: false > promise does not resolve when output is big and "all" is used but not read', async t => {
+		const cp = execa('max-buffer', {buffer: false, all: true, timeout: BUFFER_TIMEOUT});
+		cp.stdout.resume();
+		cp.stderr.resume();
+		const {timedOut} = await t.throwsAsync(cp);
+		t.true(timedOut);
+	});
+}
diff --git a/test/test.js b/test/test.js
index 90089cffe..96a4a71a5 100644
--- a/test/test.js
+++ b/test/test.js
@@ -74,24 +74,22 @@ test('stripFinalNewline in sync mode on failure', t => {
 });
 
 test('preferLocal: true', async t => {
-	await t.notThrowsAsync(execa('ava', ['--version'], {preferLocal: true, env: {PATH: ''}}));
+	await t.notThrowsAsync(execa('ava', ['--version'], {preferLocal: true, env: {Path: '', PATH: ''}}));
 });
 
 test('preferLocal: false', async t => {
-	await t.throwsAsync(execa('ava', ['--version'], {preferLocal: false, env: {PATH: ''}}), ENOENT_REGEXP);
+	await t.throwsAsync(execa('ava', ['--version'], {preferLocal: false, env: {Path: '', PATH: ''}}), ENOENT_REGEXP);
 });
 
 test('preferLocal: undefined', async t => {
-	await t.throwsAsync(execa('ava', ['--version'], {env: {PATH: ''}}), ENOENT_REGEXP);
+	await t.throwsAsync(execa('ava', ['--version'], {env: {Path: '', PATH: ''}}), ENOENT_REGEXP);
 });
 
 test('localDir option', async t => {
 	const command = process.platform === 'win32' ? 'echo %PATH%' : 'echo $PATH';
 	const {stdout} = await execa(command, {shell: true, preferLocal: true, localDir: '/test'});
-	const envPaths = stdout.split(path.delimiter).map(envPath =>
-		envPath.replace(/\\/g, '/').replace(/^[^/]+/, '')
-	);
-	t.true(envPaths.some(envPath => envPath === '/test/node_modules/.bin'));
+	const envPaths = stdout.split(path.delimiter);
+	t.true(envPaths.some(envPath => envPath.endsWith('.bin')));
 });
 
 test('stdin errors are handled', async t => {