promtool: Add testcase for detecting duplicates

Introduce a basic test for checking for duplicate rules.

Signed-off-by: Holger Hans Peter Freyther <holger@moiji-mobile.com>

cmd/promtool/main_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/prometheus/prometheus/pkg/rulefmt"
 	"github.com/stretchr/testify/require"
 )
 
@@ -118,3 +119,35 @@ func TestCheckSDFile(t *testing.T) {
 		})
 	}
 }
+
+func TestCheckDuplicates(t *testing.T) {
+	cases := []struct {
+		name         string
+		ruleFile     string
+		expectedDups []compareRuleType
+	}{
+		{
+			name:     "no duplicates",
+			ruleFile: "./testdata/rules.yml",
+		},
+		{
+			name:     "duplicate in other group",
+			ruleFile: "./testdata/rules_duplicates.yml",
+			expectedDups: []compareRuleType{
+				{
+					metric: "job:test:count_over_time1m",
+				},
+			},
+		},
+	}
+
+	for _, test := range cases {
+		c := test
+		t.Run(c.name, func(t *testing.T) {
+			rgs, err := rulefmt.ParseFile(c.ruleFile)
+			require.Empty(t, err)
+			dups := checkDuplicates(rgs.Groups)
+			require.Equal(t, c.expectedDups, dups)
+		})
+	}
+}

cmd/promtool/testdata/rules_duplicates.yml

@@ -0,0 +1,24 @@
+# This is a rules file with duplicate expressions
+
+groups:
+  - name: base
+    rules:
+      - record: job:test:count_over_time1m
+        expr: sum without(instance) (count_over_time(test[1m]))
+
+      # A recording rule that doesn't depend on input series.
+      - record: fixed_data
+        expr: 1
+
+      # Subquery with default resolution test.
+      - record: suquery_interval_test
+        expr: count_over_time(up[5m:])
+
+      # Duplicating
+      - record: job:test:count_over_time1m
+        expr: sum without(instance) (count_over_time(test[1m]))
+
+  - name: duplicate
+    rules:
+      - record: job:test:count_over_time1m
+        expr: sum without(instance) (count_over_time(test[1m]))