Add typescript for type checking

libraries/o-error/test/http.test.js

@@ -1,3 +1,5 @@
+const { expect } = require('chai')
+
 const HttpErrors = require('../http')
 
 const { expectError } = require('./support')

libraries/o-error/test/o-error-util.test.js

@@ -1,4 +1,5 @@
 const { getFullInfo, getFullStack, hasCauseInstanceOf } = require('..')
+const { expect } = require('chai')
 
 describe('OError.getFullInfo', function () {
   it('works on a normal error', function () {

libraries/o-error/test/o-error.test.js

@@ -1,3 +1,5 @@
+const { expect } = require('chai')
+
 const OError = require('..')
 const { expectError } = require('./support')
 

libraries/o-error/test/support/index.js

@@ -1,8 +1,6 @@
-'use strict'
+const { expect } = require('chai')
 
-var chai = require('chai')
-
-global.expect = chai.expect
+const OError = require('../..')
 
 exports.expectError = function OErrorExpectError(e, expected) {
   // should set the name to the error's name