Added unit test for util.getNonBlockingReadSize() (#513)

.luacheckrc

@@ -14,10 +14,11 @@ read_globals = {
 
 exclude_files = {
     "build/*",
-    "spec/*",
     "thirdparty/*",
 }
 
+files["spec/unit/*"].std = "+busted"
+
 -- TODO: clean up and enforce max line width (631)
 ignore = {
     "631",

spec/unit/util_spec.lua

@@ -141,7 +141,7 @@ describe("util module", function()
 
     describe("util.purgeDir", function()
         it("should error out on non-exists directory", function()
-            ok, err = util.purgeDir('/tmp/123/abc/567/foobar')
+            local ok, err = util.purgeDir('/tmp/123/abc/567/foobar')
             assert.is_nil(ok)
             assert.is_not_nil(err)
         end)
@@ -160,4 +160,24 @@ describe("util module", function()
             assert.is_not_nil(err)
         end)
     end)
+
+    describe("util.getNonBlockingReadSize", function()
+        it("should read pipe when data is available", function()
+            if not util.isAndroid() then
+                local std_out = io.popen("sleep 3; echo 'done'", "r")
+                assert.are.equal(util.getNonBlockingReadSize(std_out), 0)
+                util.sleep(1)
+                assert.are.equal(util.getNonBlockingReadSize(std_out), 0)
+                util.sleep(1)
+                assert.are.equal(util.getNonBlockingReadSize(std_out), 0)
+                util.sleep(2)
+                assert.are.equal(util.getNonBlockingReadSize(std_out), 5)
+                local startsec = util.gettime()
+                local data = std_out:read("*all")
+                local donesec = util.gettime()
+                assert.are.equal(data, "done\n")
+                assert.is_true(donesec - startsec <= 1)
+            end
+        end)
+    end)
 end)