Updates build file unit tests to be Windows Compatible (elastic#24296)

POSTIX permissions are not available on windows and libuv reports only
666 and 444 for if it's read or writeable.

Additionally, on Windows and being reported on OSX, modifying directory
timestamps in the same stream often does not work.

Signed-off-by: Tyler Smalley <tyler.smalley@elastic.co>

src/dev/build/lib/__tests__/fs.js

@@ -31,6 +31,8 @@ const FOO_TAR_PATH = resolve(FIXTURES, 'foo_dir.tar.gz');
 const BAR_TXT_PATH = resolve(FIXTURES, 'foo_dir/bar.txt');
 const WORLD_EXECUTABLE = resolve(FIXTURES, 'bin/world_executable');
 
+const isWindows = /^win/.test(process.platform);
+
 // get the mode of a file as a string, like 777, or 644,
 function getCommonMode(path) {
   return statSync(path).mode.toString(8).slice(-3);
@@ -184,7 +186,8 @@ describe('dev/build/lib/fs', () => {
     it('copies the mode of the source file', async () => {
       const destination = resolve(TMP, 'dest.txt');
       await copy(WORLD_EXECUTABLE, destination);
-      expect(getCommonMode(destination)).to.be('777');
+
+      expect(getCommonMode(destination)).to.be(isWindows ? '666' : '777');
     });
   });
 
@@ -225,8 +228,8 @@ describe('dev/build/lib/fs', () => {
         resolve(destination, 'foo_dir/foo'),
       ]);
 
-      expect(getCommonMode(resolve(destination, 'bin/world_executable'))).to.be('777');
-      expect(getCommonMode(resolve(destination, 'foo_dir/bar.txt'))).to.be('644');
+      expect(getCommonMode(resolve(destination, 'bin/world_executable'))).to.be(isWindows ? '666' : '777');
+      expect(getCommonMode(resolve(destination, 'foo_dir/bar.txt'))).to.be(isWindows ? '666' : '644');
     });
 
     it('applies select globs if specified, ignores dot files', async () => {
@@ -270,6 +273,7 @@ describe('dev/build/lib/fs', () => {
       expect(await read(resolve(destination, 'foo_dir/.bar'))).to.be('dotfile\n');
     });
 
+
     it('supports atime and mtime', async () => {
       const destination = resolve(TMP, 'a/b/c/d/e');
       const time = new Date(1425298511000);

src/dev/build/lib/fs.js

@@ -129,9 +129,22 @@ export async function copyAll(sourceDir, destination, options = {}) {
       base: sourceDir,
       dot,
     }),
-    vfs.dest(destination),
-    ...(Boolean(time) ? [createMapStream(file => utimesAsync(file.path, time, time))] : []),
+    vfs.dest(destination)
   ]);
+
+  // we must update access and modified file times after the file copy
+  // has completed, otherwise the copy action can effect modify times.
+  if (Boolean(time)) {
+    await createPromiseFromStreams([
+      vfs.src(select, {
+        buffer: false,
+        cwd: destination,
+        base: destination,
+        dot,
+      }),
+      createMapStream(file => utimesAsync(file.path, time, time))
+    ]);
+  }
 }
 
 export async function getFileHash(path, algo) {