Add more coverage for air check unchanged file (#290)

* add test case for filechecksum

Author: xiantang

runner/engine.go

@@ -63,13 +63,10 @@ func NewEngine(cfgPath string, debugMode bool) (*Engine, error) {
 		canExit:        make(chan bool, 1),
 		binStopCh:      make(chan bool),
 		exitCh:         make(chan bool),
+		fileChecksums:  &checksumMap{m: make(map[string]string)},
 		watchers:       0,
 	}
 
-	if cfg.Build.ExcludeUnchanged {
-		e.fileChecksums = &checksumMap{m: make(map[string]string)}
-	}
-
 	return &e, nil
 }
 

runner/engine_test.go

@@ -128,6 +128,7 @@ func TestRebuild(t *testing.T) {
 		t.Fatalf("Should not be fail: %s.", err)
 	}
 	engine, err := NewEngine("", true)
+	engine.config.Build.ExcludeUnchanged = true
 	if err != nil {
 		t.Fatalf("Should not be fail: %s.", err)
 	}