fix: dont default find root option to anything

This ensures that it will only short circuit if a valid path is passed
in.

This commit also adds one more mocked test to ensure that the system
root path is always checked as the last path and no path is checked
twice.

lib/find.js

@@ -1,7 +1,7 @@
 const is = require('./is.js')
-const { dirname, sep } = require('path')
+const { dirname } = require('path')
 
-module.exports = async ({ cwd = process.cwd(), root = sep } = {}) => {
+module.exports = async ({ cwd = process.cwd(), root } = {}) => {
   while (true) {
     if (await is({ cwd })) {
       return cwd

test/find.js

@@ -1,32 +1,30 @@
 const t = require('tap')
-const { join } = require('path')
+const { join, parse } = require('path')
+const { tmpdir } = require('os')
 const find = require('../lib/find.js')
 
 t.test('find the git dir many folders up', t => {
   const root = t.testdir({
     '.git': { index: 'hello' },
     a: { b: { c: { d: { e: {} } } } },
   })
-  const path = `${root}/a/b/c/d/e`
-  return t.resolveMatch(find({ cwd: path }), root)
+  return t.resolveMatch(find({ cwd: join(root, 'a/b/c/d/e') }), root)
 })
 
 t.test('stop before root dir', t => {
   const root = t.testdir({
     '.git': { index: 'hello' },
     a: { b: { c: { d: { e: {} } } } },
   })
-  const path = `${root}/a/b/c/d/e`
-  return t.resolveMatch(find({ cwd: path, root: join(root, 'a') }), null)
+  return t.resolveMatch(find({ cwd: join(root, 'a/b/c/d/e'), root: join(root, 'a') }), null)
 })
 
 t.test('stop at root dir', t => {
   const root = t.testdir({
     '.git': { index: 'hello' },
     a: { b: { c: { d: { e: {} } } } },
   })
-  const path = `${root}/a/b/c/d/e`
-  return t.resolveMatch(find({ cwd: path, root }), root)
+  return t.resolveMatch(find({ cwd: join(root, 'a/b/c/d/e'), root }), root)
 })
 
 t.test('find the git dir at current level', t => {
@@ -38,13 +36,40 @@ t.test('find the git dir at current level', t => {
 
 t.test('no git dir to find', t => {
   // this will fail if your tmpdir is in a git repo, I suppose
-  const path = require('os').tmpdir()
-  return t.resolveMatch(find({ cwd: path }), null)
+  return t.resolveMatch(find({ cwd: tmpdir() }), null)
 })
 
 t.test('default to cwd', t => {
-  // this will fail if your tmpdir is in a git repo, I suppose
-  const path = require('os').tmpdir()
-  process.chdir(path)
+  const dir = process.cwd()
+  t.teardown(() => process.chdir(dir))
+  process.chdir(tmpdir())
   return t.resolveMatch(find(), null)
 })
+
+t.test('mock is', async t => {
+  const mockFind = async (t, opts) => {
+    const seen = []
+    const mocked = t.mock('../lib/find.js', {
+      '../lib/is.js': async (o) => {
+        seen.push(o.cwd)
+        return false
+      },
+    })
+    const cwd = tmpdir()
+    const root = parse(cwd).root
+    return [await mocked({ cwd: tmpdir(), ...opts }), seen, root]
+  }
+
+  await t.test('no git dir to find', async t => {
+    const [res, seen, root] = await mockFind(t)
+    t.strictSame(res, null)
+    t.strictSame(seen, [...new Set(seen)], 'no directory checked more than once')
+    t.equal(seen[seen.length - 1], root, 'last dir is root')
+  })
+
+  await t.test('root is never found', async t => {
+    const [res, seen, root] = await mockFind(t, { root: 1 })
+    t.strictSame(res, null)
+    t.equal(seen[seen.length - 1], root, 'last dir is root')
+  })
+})