add tests and remove unused method in inotify

internal/fswatcher/inotify/inotify.go

@@ -130,18 +130,6 @@ func (i *Inotify) NumWatchers() int {
 	return len(i.Watchers)
 }
 
-func (i *Inotify) String() string {
-	if len(i.Watchers) < 20 {
-		dirs := make([]string, 0)
-		for _, w := range i.Watchers {
-			dirs = append(dirs, w.Dir)
-		}
-		return fmt.Sprintf("Watching: %v", dirs)
-	} else {
-		return fmt.Sprintf("Watching %d directories", len(i.Watchers))
-	}
-}
-
 func getMaxWatchers() (int, error) {
 	b, err := ioutil.ReadFile(maximumWatchersFile)
 	if err != nil {

internal/psscanner/psscanner_test.go

@@ -0,0 +1,63 @@
+package psscanner
+
+import (
+	"testing"
+	"time"
+)
+
+const timeout = 100 * time.Millisecond
+
+// refresh
+
+func TestRun(t *testing.T) {
+	tests := []struct {
+		pids   []int
+		events []string
+	}{
+		{pids: []int{1, 2, 3}, events: []string{
+			"UID=???  PID=3      | the-command",
+			"UID=???  PID=2      | the-command",
+			"UID=???  PID=1      | the-command",
+		}},
+	}
+
+	for _, tt := range tests {
+		restoreGetPIDs := mockPidList(tt.pids)
+		restoreCmdLineReader := mockCmdLineReader([]byte("the-command"), nil)
+		restoreProcStatusReader := mockProcStatusReader([]byte(""), nil) // don't mock read value since it's not worth it
+
+		pss := NewPSScanner()
+		triggerCh := make(chan struct{})
+		eventCh, errCh := pss.Run(triggerCh)
+
+		// does nothing without triggering
+		select {
+		case e := <-eventCh:
+			t.Errorf("Received event before trigger: %s", e)
+		case err := <-errCh:
+			t.Errorf("Received error before trigger: %v", err)
+		case <-time.After(timeout):
+			// ok
+		}
+
+		triggerCh <- struct{}{}
+
+		// received event after the trigger
+		for i := 0; i < 3; i++ {
+			select {
+			case <-time.After(timeout):
+				t.Errorf("did not receive event in time")
+			case e := <-eventCh:
+				if e != tt.events[i] {
+					t.Errorf("Wrong event received: got '%s' but wanted '%s'", e, tt.events[i])
+				}
+			case err := <-errCh:
+				t.Errorf("Received unexpected error: %v", err)
+			}
+		}
+
+		restoreProcStatusReader()
+		restoreCmdLineReader()
+		restoreGetPIDs()
+	}
+}