looks like there is whitespace on Windows

packages/dd-trace/test/check_require_cache.spec.js

@@ -14,38 +14,19 @@ describe('check_require_cache', () => {
 
   it('should be no warnings when tracer is loaded first', (done) => {
     exec(`${process.execPath} ./check_require_cache/good-order.js`, opts, (error, stdout, stderr) => {
-      if (error) {
-        return done(error)
-      }
-
-      if (stdout) {
-        return done(stdout)
-      }
-
-      if (stderr) {
-        return done(stderr)
-      }
-
+      expect(error).to.be.null
+      expect(stdout).to.be.empty
+      expect(stderr).to.be.empty
       done()
     })
   })
 
   it('should find warnings when tracer loaded late', (done) => {
     exec(`${process.execPath} ./check_require_cache/bad-order.js`, opts, (error, stdout, stderr) => {
-      if (error) {
-        return done(error)
-      }
-
-      if (stdout) {
-        return done(stdout)
-      }
-
-      if (!stderr) {
-        return done('expected an error string')
-      }
-
+      expect(error).to.be.null
+      expect(stdout).to.be.empty
+      expect(stderr).to.not.be.empty
       expect(stderr).to.include("Package 'express' was loaded")
-
       done()
     })
   })