From b29fe584344181091d96f690ed3716942f24a722 Mon Sep 17 00:00:00 2001
From: Ken Hibino <ken.hibino7@gmail.com>
Date: Thu, 10 Mar 2022 11:06:48 -0800
Subject: [PATCH] Implement RDB.ListGroups

---
 internal/asynqtest/asynqtest.go |  4 ++-
 internal/rdb/rdb.go             |  8 +++--
 internal/rdb/rdb_test.go        | 61 +++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/internal/asynqtest/asynqtest.go b/internal/asynqtest/asynqtest.go
index 6c7a35c..1bd9c3c 100644
--- a/internal/asynqtest/asynqtest.go
+++ b/internal/asynqtest/asynqtest.go
@@ -248,7 +248,9 @@ func SeedCompletedQueue(tb testing.TB, r redis.UniversalClient, entries []base.Z
 // SeedGroup initializes the group with the given entries.
 func SeedGroup(tb testing.TB, r redis.UniversalClient, entries []base.Z, qname, gname string) {
 	tb.Helper()
-	r.SAdd(context.Background(), base.AllQueues, qname)
+	ctx := context.Background()
+	r.SAdd(ctx, base.AllQueues, qname)
+	r.SAdd(ctx, base.AllGroups(qname), gname)
 	seedRedisZSet(tb, r, base.GroupKey(qname, gname), entries, base.TaskStateAggregating)
 }
 
diff --git a/internal/rdb/rdb.go b/internal/rdb/rdb.go
index cb282c5..d203e37 100644
--- a/internal/rdb/rdb.go
+++ b/internal/rdb/rdb.go
@@ -985,8 +985,12 @@ func (r *RDB) forwardAll(qname string) (err error) {
 
 // ListGroups returns a list of all known groups in the given queue.
 func (r *RDB) ListGroups(qname string) ([]string, error) {
-	// TODO: Implement this with TDD
-	return nil, nil
+	var op errors.Op = "RDB.ListGroups"
+	groups, err := r.client.SMembers(context.Background(), base.AllGroups(qname)).Result()
+	if err != nil {
+		return nil, errors.E(op, errors.Unknown, &errors.RedisCommandError{Command: "smembers", Err: err})
+	}
+	return groups, nil
 }
 
 // TODO: Add comment describing what the script does.
diff --git a/internal/rdb/rdb_test.go b/internal/rdb/rdb_test.go
index 903f04f..38a1fc6 100644
--- a/internal/rdb/rdb_test.go
+++ b/internal/rdb/rdb_test.go
@@ -3331,3 +3331,64 @@ func TestDeleteAggregationSet(t *testing.T) {
 		}
 	}
 }
+
+func TestListGroups(t *testing.T) {
+	r := setup(t)
+	defer r.Close()
+
+	now := time.Now()
+	m1 := h.NewTaskMessageBuilder().SetQueue("default").SetGroup("foo").Build()
+	m2 := h.NewTaskMessageBuilder().SetQueue("default").SetGroup("bar").Build()
+	m3 := h.NewTaskMessageBuilder().SetQueue("custom").SetGroup("baz").Build()
+	m4 := h.NewTaskMessageBuilder().SetQueue("custom").SetGroup("qux").Build()
+
+	tests := []struct {
+		groups map[string]map[string][]base.Z
+		qname  string
+		want   []string
+	}{
+		{
+			groups: map[string]map[string][]base.Z{
+				"default": {
+					"foo": {{Message: m1, Score: now.Add(-10 * time.Second).Unix()}},
+					"bar": {{Message: m2, Score: now.Add(-10 * time.Second).Unix()}},
+				},
+				"custom": {
+					"baz": {{Message: m3, Score: now.Add(-10 * time.Second).Unix()}},
+					"qux": {{Message: m4, Score: now.Add(-10 * time.Second).Unix()}},
+				},
+			},
+			qname: "default",
+			want:  []string{"foo", "bar"},
+		},
+		{
+			groups: map[string]map[string][]base.Z{
+				"default": {
+					"foo": {{Message: m1, Score: now.Add(-10 * time.Second).Unix()}},
+					"bar": {{Message: m2, Score: now.Add(-10 * time.Second).Unix()}},
+				},
+				"custom": {
+					"baz": {{Message: m3, Score: now.Add(-10 * time.Second).Unix()}},
+					"qux": {{Message: m4, Score: now.Add(-10 * time.Second).Unix()}},
+				},
+			},
+			qname: "custom",
+			want:  []string{"baz", "qux"},
+		},
+	}
+
+	for _, tc := range tests {
+		h.FlushDB(t, r.client)
+		h.SeedAllGroups(t, r.client, tc.groups)
+
+		got, err := r.ListGroups(tc.qname)
+		if err != nil {
+			t.Errorf("ListGroups returned error: %v", err)
+			continue
+		}
+
+		if diff := cmp.Diff(tc.want, got, h.SortStringSliceOpt); diff != "" {
+			t.Errorf("ListGroups=%v, want=%v; (-want,+got)\n%s", got, tc.want, diff)
+		}
+	}
+}