From ada8a6ef10c37ec0ea37b2e0c21e4ec2187a6fa8 Mon Sep 17 00:00:00 2001
From: Oleg Zaytsev <mail@olegzaytsev.com>
Date: Fri, 27 Sep 2024 10:14:39 +0200
Subject: [PATCH] Add some more tests for MemPostings_Delete

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
---
 tsdb/index/postings_test.go | 86 +++++++++++++++++++++++++------------
 1 file changed, 59 insertions(+), 27 deletions(-)

diff --git a/tsdb/index/postings_test.go b/tsdb/index/postings_test.go
index 1802c9e891..b41fb54e65 100644
--- a/tsdb/index/postings_test.go
+++ b/tsdb/index/postings_test.go
@@ -973,37 +973,69 @@ func TestMemPostingsStats(t *testing.T) {
 }
 
 func TestMemPostings_Delete(t *testing.T) {
-	p := NewMemPostings()
-	p.Add(1, labels.FromStrings("lbl1", "a"))
-	p.Add(2, labels.FromStrings("lbl1", "b"))
-	p.Add(3, labels.FromStrings("lbl2", "a"))
+	t.Run("some postings", func(t *testing.T) {
+		p := NewMemPostings()
+		p.Add(1, labels.FromStrings("lbl1", "a"))
+		p.Add(2, labels.FromStrings("lbl1", "b"))
+		p.Add(3, labels.FromStrings("lbl2", "a"))
 
-	before := p.Get(allPostingsKey.Name, allPostingsKey.Value)
-	deletedRefs := map[storage.SeriesRef]struct{}{
-		2: {},
-	}
-	affectedLabels := map[labels.Label]struct{}{
-		{Name: "lbl1", Value: "b"}: {},
-	}
-	p.Delete(deletedRefs, affectedLabels)
-	after := p.Get(allPostingsKey.Name, allPostingsKey.Value)
+		before := p.Get(allPostingsKey.Name, allPostingsKey.Value)
+		deletedRefs := map[storage.SeriesRef]struct{}{
+			2: {},
+		}
+		affectedLabels := map[labels.Label]struct{}{
+			{Name: "lbl1", Value: "b"}: {},
+		}
+		p.Delete(deletedRefs, affectedLabels)
+		after := p.Get(allPostingsKey.Name, allPostingsKey.Value)
 
-	// Make sure postings gotten before the delete have the old data when
-	// iterated over.
-	expanded, err := ExpandPostings(before)
-	require.NoError(t, err)
-	require.Equal(t, []storage.SeriesRef{1, 2, 3}, expanded)
+		// Make sure postings gotten before the delete have the old data when
+		// iterated over.
+		expanded, err := ExpandPostings(before)
+		require.NoError(t, err)
+		require.Equal(t, []storage.SeriesRef{1, 2, 3}, expanded)
 
-	// Make sure postings gotten after the delete have the new data when
-	// iterated over.
-	expanded, err = ExpandPostings(after)
-	require.NoError(t, err)
-	require.Equal(t, []storage.SeriesRef{1, 3}, expanded)
+		// Make sure postings gotten after the delete have the new data when
+		// iterated over.
+		expanded, err = ExpandPostings(after)
+		require.NoError(t, err)
+		require.Equal(t, []storage.SeriesRef{1, 3}, expanded)
 
-	deleted := p.Get("lbl1", "b")
-	expanded, err = ExpandPostings(deleted)
-	require.NoError(t, err)
-	require.Empty(t, expanded, "expected empty postings, got %v", expanded)
+		deleted := p.Get("lbl1", "b")
+		expanded, err = ExpandPostings(deleted)
+		require.NoError(t, err)
+		require.Empty(t, expanded, "expected empty postings, got %v", expanded)
+	})
+
+	t.Run("all postings", func(t *testing.T) {
+		p := NewMemPostings()
+		p.Add(1, labels.FromStrings("lbl1", "a"))
+		p.Add(2, labels.FromStrings("lbl1", "b"))
+		p.Add(3, labels.FromStrings("lbl2", "a"))
+
+		deletedRefs := map[storage.SeriesRef]struct{}{1: {}, 2: {}, 3: {}}
+		affectedLabels := map[labels.Label]struct{}{
+			{Name: "lbl1", Value: "a"}: {},
+			{Name: "lbl1", Value: "b"}: {},
+			{Name: "lbl1", Value: "c"}: {},
+		}
+		p.Delete(deletedRefs, affectedLabels)
+		after := p.Get(allPostingsKey.Name, allPostingsKey.Value)
+		expanded, err := ExpandPostings(after)
+		require.NoError(t, err)
+		require.Empty(t, expanded)
+	})
+
+	t.Run("nothing on empty mempostings", func(t *testing.T) {
+		p := NewMemPostings()
+		deletedRefs := map[storage.SeriesRef]struct{}{}
+		affectedLabels := map[labels.Label]struct{}{}
+		p.Delete(deletedRefs, affectedLabels)
+		after := p.Get(allPostingsKey.Name, allPostingsKey.Value)
+		expanded, err := ExpandPostings(after)
+		require.NoError(t, err)
+		require.Empty(t, expanded)
+	})
 }
 
 // BenchmarkMemPostings_Delete is quite heavy, so consider running it with