implement RecordQueue type

internal/record_test.go

@@ -0,0 +1,59 @@
+package internal
+
+import (
+	"testing"
+)
+
+func TestRecordQueue_Push(t *testing.T) {
+	var recCount int
+	newRecord := func() Record {
+		recCount++
+		return testRecord{
+			id: recCount,
+		}
+	}
+
+	var rq RecordQueue
+	if rq.Len() != 0 {
+		t.Fatalf("zero value should have zero lenght")
+	}
+
+	_, ok := rq.Pop()
+	if ok {
+		t.Fatalf("Pop() should return (_,false) on a zero value")
+	}
+
+	rq.Push(nil)
+	if rq.Len() != 0 {
+		t.Fatalf("pushing nil should be a no-op")
+	}
+
+	rq.Push(newRecord())
+	if rq.Len() != 1 {
+		t.Fatalf("pushing 1st record should result in lenght of 1")
+	}
+
+	rq.Push(newRecord())
+	if rq.Len() != 2 {
+		t.Fatalf("pushing 2nd record should result in lenght of 2")
+	}
+
+	rec, 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.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")
+	}
+}
+
+type testRecord struct {
+	Record
+
+	id int
+}