implement and test the Peek for the RecordQueue type

internal/record_test.go

@@ -14,6 +14,7 @@ func TestRecordQueue(t *testing.T) {
 	}
 
 	var rq RecordQueue
+
 	if rq.Len() != 0 {
 		t.Fatalf("zero value should have zero lenght")
 	}
@@ -23,6 +24,11 @@ func TestRecordQueue(t *testing.T) {
 		t.Fatalf("Pop() should return (_,false) on a zero value")
 	}
 
+	_, ok = rq.Peek()
+	if ok {
+		t.Fatalf("Peek() should return (_,false) on a zero value")
+	}
+
 	rq.Push(nil)
 	if rq.Len() != 0 {
 		t.Fatalf("pushing nil should be a no-op")
@@ -38,18 +44,39 @@ func TestRecordQueue(t *testing.T) {
 		t.Fatalf("pushing 2nd record should result in lenght of 2")
 	}
 
-	rec, ok := rq.Pop()
+	peekRec, ok := rq.Peek()
+	if !ok {
+		t.Fatalf("Peek() should return (_,true) when the list is not empty")
+	}
+
+	if peekRec, ok := peekRec.(testRecord); ok {
+		if peekRec.id != 1 {
+			t.Fatalf("Peek() should return the 1st record pushed but returned %d", peekRec.id)
+		}
+	} else {
+		t.Fatalf("Peek() should return the original record type")
+	}
+
+	if rq.Len() != 2 {
+		t.Fatalf("Peek() should not affect the list length")
+	}
+
+	popRec, ok := rq.Pop()
 	if !ok {
 		t.Fatalf("Pop() should return (_,true) when the list is not empty")
 	}
 
-	if rec, ok := rec.(testRecord); ok {
+	if rec, ok := popRec.(testRecord); ok {
 		if rec.id != 1 {
 			t.Fatalf("Pop() should return the first record pushed but returned %d", rec.id)
 		}
 	} else {
 		t.Fatalf("Pop() should return the original record")
 	}
+
+	if rq.Len() != 1 {
+		t.Fatalf("Pop() should remove an element from the list")
+	}
 }
 
 func TestRecordQueueNilReceiver(t *testing.T) {
@@ -59,7 +86,12 @@ func TestRecordQueueNilReceiver(t *testing.T) {
 		t.Fatalf("nil receiver should have zero lenght")
 	}
 
-	_, ok := rq.Pop()
+	_, ok := rq.Peek()
+	if ok {
+		t.Fatalf("Peek() on a nil receiver should return (_,false)")
+	}
+
+	_, ok = rq.Pop()
 	if ok {
 		t.Fatalf("Pop() on a nil receiver should return (_,false)")
 	}