Add unit tests for pkg/sharding/consistenthash

Author: timebertt

pkg/sharding/consistenthash/consistenthash_suite_test.go

@@ -0,0 +1,29 @@
+/*
+Copyright 2025 Tim Ebert.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package consistenthash_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestConsistentHash(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Consistent Hash Suite")
+}

pkg/sharding/consistenthash/ring_test.go

@@ -0,0 +1,91 @@
+/*
+Copyright 2025 Tim Ebert.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package consistenthash_test
+
+import (
+	"strings"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	. "github.com/timebertt/kubernetes-controller-sharding/pkg/sharding/consistenthash"
+)
+
+var _ = Describe("Ring", func() {
+	Describe("#New", func() {
+		It("should initialize a new Ring", func() {
+			ring := New(nil, 0, "foo")
+			Expect(ring).NotTo(BeNil())
+			Expect(ring.IsEmpty()).To(BeFalse())
+		})
+	})
+
+	Describe("#IsEmpty", func() {
+		It("should true if there are no nodes", func() {
+			ring := New(nil, 0)
+			Expect(ring.IsEmpty()).To(BeTrue())
+			ring.AddNodes("foo")
+			Expect(ring.IsEmpty()).To(BeFalse())
+		})
+	})
+
+	Describe("#Hash", func() {
+		It("should use the configured hash function", func() {
+			ring := New(func(data string) uint64 {
+				if strings.HasPrefix(data, "foo") {
+					// map all foo* nodes and keys to 1
+					return 1
+				}
+				return 2
+			}, 1, "foo", "bar")
+
+			Expect(ring.Hash("foo")).To(Equal("foo"))
+			Expect(ring.Hash("bar")).To(Equal("bar"))
+			Expect(ring.Hash("baz")).To(Equal("bar"))
+		})
+
+		It("should use the default hash function", func() {
+			ring := New(nil, 0, "foo", "bar")
+
+			Expect(ring.Hash("1")).NotTo(Equal(ring.Hash("10")))
+		})
+
+		It("should return the empty string if there are no nodes", func() {
+			ring := New(nil, 0)
+
+			Expect(ring.Hash("foo")).To(BeEmpty())
+		})
+
+		It("should return the first node when walking the whole ring", func() {
+			ring := New(func(data string) uint64 {
+				if strings.HasPrefix(data, "foo") {
+					// map all foo* nodes and keys to 1
+					return 1
+				}
+				if strings.HasPrefix(data, "bar") {
+					// map all bar* nodes and keys to 1
+					return 2
+				}
+				return 3
+			}, 1, "foo", "bar")
+
+			Expect(ring.Hash("foo")).To(Equal("foo"))
+			Expect(ring.Hash("bar")).To(Equal("bar"))
+			Expect(ring.Hash("baz")).To(Equal("foo"))
+		})
+	})
+})