diff --git a/__mocks__/@actions/github.ts b/__mocks__/@actions/github.ts
new file mode 100644
index 0000000..4f68ece
--- /dev/null
+++ b/__mocks__/@actions/github.ts
@@ -0,0 +1,41 @@
+const mockApi = {
+  rest: {
+    issues: {
+      addLabels: jest.fn(),
+      removeLabel: jest.fn(),
+    },
+    pulls: {
+      get: jest.fn().mockResolvedValue({}),
+      listFiles: {
+        endpoint: {
+          merge: jest.fn().mockReturnValue({}),
+        },
+      },
+    },
+    repos: {
+      getContent: jest.fn(),
+      listReleases: jest.fn(),
+      createRelease: jest.fn(),
+      updateRelease: jest.fn(),
+      generateReleaseNotes: jest.fn(),
+    },
+  },
+  paginate: jest.fn().mockImplementation(async (method, options) => {
+    const response = await method(options)
+    return response.data
+  }),
+}
+export const context = {
+  payload: {
+    pull_request: {
+      number: 123,
+    },
+  },
+  repo: {
+    owner: 'monalisa',
+    repo: 'helloworld',
+  },
+  ref: 'refs/heads/main',
+}
+
+export const getOctokit = jest.fn().mockImplementation(() => mockApi)
diff --git a/__tests__/release.test.ts b/__tests__/release.test.ts
new file mode 100644
index 0000000..35affa3
--- /dev/null
+++ b/__tests__/release.test.ts
@@ -0,0 +1,236 @@
+import {getRelease, createOrUpdateRelease} from '../src/release'
+import * as github from '@actions/github'
+import {Inputs} from '../src/context'
+
+const fs = jest.requireActual('fs')
+
+jest.mock('@actions/core')
+jest.mock('@actions/github')
+
+let gh: ReturnType<typeof github.getOctokit>
+
+describe('getRelease', () => {
+  beforeEach(() => {
+    jest.clearAllMocks()
+    gh = github.getOctokit('_')
+  })
+
+  it('should return the latest release when multiple releases exist', async () => {
+    const mockResponse: any = {
+      headers: {},
+      status: 200,
+      data: [
+        {
+          tag_name: 'v1.0.2',
+          target_commitish: 'main',
+          draft: false,
+        },
+        {
+          tag_name: 'v1.0.1',
+          target_commitish: 'main',
+          draft: false,
+        },
+        {
+          tag_name: 'v1.0.0',
+          target_commitish: 'main',
+          draft: false,
+        },
+      ],
+    }
+
+    const mockReleases = jest.spyOn(gh.rest.repos, 'listReleases')
+    mockReleases.mockResolvedValue(mockResponse)
+
+    const [releases, latestRelease] = await getRelease(gh)
+
+    expect(releases).toHaveLength(3)
+    expect(latestRelease).toBe('v1.0.2')
+  })
+
+  it('should return the latest for the current branch', async () => {
+    const mockResponse: any = {
+      headers: {},
+      status: 200,
+      data: [
+        {
+          tag_name: 'v1.0.2',
+          target_commitish: 'dev',
+          draft: false,
+        },
+        {
+          tag_name: 'v1.0.1',
+          target_commitish: 'main',
+          draft: false,
+        },
+        {
+          tag_name: 'v1.0.0',
+          target_commitish: 'main',
+          draft: false,
+        },
+      ],
+    }
+
+    const mockReleases = jest.spyOn(gh.rest.repos, 'listReleases')
+    mockReleases.mockResolvedValue(mockResponse)
+
+    const [releases, latestRelease] = await getRelease(gh)
+
+    expect(releases).toHaveLength(3)
+    expect(latestRelease).toBe('v1.0.1')
+  })
+
+  it('should return the latest non-draft release', async () => {
+    const mockResponse: any = {
+      headers: {},
+      status: 200,
+      data: [
+        {
+          tag_name: 'v1.0.2',
+          target_commitish: 'dev',
+          draft: false,
+        },
+        {
+          tag_name: 'v1.0.1',
+          target_commitish: 'main',
+          draft: true,
+        },
+        {
+          tag_name: 'v1.0.0',
+          target_commitish: 'main',
+          draft: false,
+        },
+      ],
+    }
+
+    const mockReleases = jest.spyOn(gh.rest.repos, 'listReleases')
+    mockReleases.mockResolvedValue(mockResponse)
+
+    const [releases, latestRelease] = await getRelease(gh)
+
+    expect(releases).toHaveLength(3)
+    expect(latestRelease).toBe('v1.0.0')
+  })
+
+  it('should return v0.0.0 when no releases exist', async () => {
+    const mockResponse: any = {
+      headers: {},
+      status: 200,
+      data: [],
+    }
+
+    const mockReleases = jest.spyOn(gh.rest.repos, 'listReleases')
+    mockReleases.mockResolvedValue(mockResponse)
+
+    const [releases, latestRelease] = await getRelease(gh)
+
+    expect(releases).toHaveLength(0)
+    expect(latestRelease).toBe('v0.0.0')
+  })
+})
+
+describe('createOrUpdateRelease', () => {
+  let mockResponse: any
+  let mockNotes: any
+  const inputs: Inputs = {
+    githubToken: '_',
+    majorLabel: 'major',
+    minorLabel: 'minor',
+    header: 'header',
+    footer: 'footer',
+  }
+  beforeEach(() => {
+    jest.clearAllMocks()
+    gh = github.getOctokit('_')
+    mockResponse = {
+      headers: {},
+      status: 200,
+      data: [
+        {
+          id: 1,
+          tag_name: 'v1.0.0',
+          target_commitish: 'main',
+          draft: false,
+          body: 'header',
+        },
+        {
+          id: 2,
+          tag_name: 'v1.0.1',
+          target_commitish: 'main',
+          draft: true,
+          body: 'header',
+        },
+      ],
+    }
+
+    mockNotes = {
+      headers: {},
+      status: 200,
+      data: {
+        body: 'header',
+        name: 'v1.0.1',
+      },
+    }
+  })
+
+  it('should create a new release draft', async () => {
+    const mockInputCreate: any = {
+      headers: {},
+      status: 200,
+      data: [
+        {
+          id: 1,
+          tag_name: 'v1.0.0',
+          target_commitish: 'main',
+          draft: false,
+        },
+      ],
+    }
+
+    const mockReleases = jest.spyOn(gh.rest.repos, 'createRelease')
+    mockReleases.mockResolvedValue(mockResponse)
+
+    const mockRelease = jest.spyOn(gh.rest.repos, 'listReleases')
+    mockRelease.mockResolvedValue(mockInputCreate)
+
+    const mockReleaseNotes = jest.spyOn(gh.rest.repos, 'generateReleaseNotes')
+    mockReleaseNotes.mockResolvedValue(mockNotes)
+
+    const response = await createOrUpdateRelease(gh, inputs, mockInputCreate.data, 'v1.0.0', 'v1.0.1')
+
+    expect(mockReleases).toHaveBeenCalledTimes(1)
+  })
+
+  it('should update an existing release draft', async () => {
+    const mockInputUpdate: any = {
+      headers: {},
+      status: 200,
+      data: [
+        {
+          id: 1,
+          tag_name: 'v1.0.0',
+          target_commitish: 'main',
+          draft: false,
+        },
+        {
+          id: 2,
+          tag_name: 'v1.0.1',
+          target_commitish: 'main',
+          draft: true,
+        },
+      ],
+    }
+
+    const mockReleases = jest.spyOn(gh.rest.repos, 'updateRelease')
+    mockReleases.mockResolvedValue(mockResponse)
+
+    const mockRelease = jest.spyOn(gh.rest.repos, 'listReleases')
+    mockRelease.mockResolvedValue(mockInputUpdate)
+
+    const mockReleaseNotes = jest.spyOn(gh.rest.repos, 'generateReleaseNotes')
+    mockReleaseNotes.mockResolvedValue(mockNotes)
+
+    const response = await createOrUpdateRelease(gh, inputs, mockInputUpdate.data, 'v1.0.0', 'v1.0.1')
+
+    expect(mockReleases).toHaveBeenCalledTimes(1)
+  })
+})
diff --git a/package-lock.json b/package-lock.json
index 33de5ed..7e5db5d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -16,6 +16,7 @@
         "semver": "^7.3.8"
       },
       "devDependencies": {
+        "@types/jest": "^29.5.0",
         "@types/js-yaml": "^4.0.5",
         "@types/node": "^18.15.3",
         "@typescript-eslint/parser": "^5.55.0",
@@ -1443,6 +1444,16 @@
         "@types/istanbul-lib-report": "*"
       }
     },
+    "node_modules/@types/jest": {
+      "version": "29.5.0",
+      "resolved": "https://registry.npmjs.org/@types/jest/-/jest-29.5.0.tgz",
+      "integrity": "sha512-3Emr5VOl/aoBwnWcH/EFQvlSAmjV+XtV9GGu5mwdYew5vhQh0IUZx/60x0TzHDu09Bi7HMx10t/namdJw5QIcg==",
+      "dev": true,
+      "dependencies": {
+        "expect": "^29.0.0",
+        "pretty-format": "^29.0.0"
+      }
+    },
     "node_modules/@types/js-yaml": {
       "version": "4.0.5",
       "resolved": "https://registry.npmjs.org/@types/js-yaml/-/js-yaml-4.0.5.tgz",
diff --git a/package.json b/package.json
index 8d47cea..0174f1c 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
     "semver": "^7.3.8"
   },
   "devDependencies": {
+    "@types/jest": "^29.5.0",
     "@types/js-yaml": "^4.0.5",
     "@types/node": "^18.15.3",
     "@typescript-eslint/parser": "^5.55.0",
diff --git a/tsconfig.json b/tsconfig.json
index f6e7cb5..9416c69 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,12 +1,16 @@
 {
   "compilerOptions": {
-    "target": "es6",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
-    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
-    "outDir": "./lib",                        /* Redirect output structure to the directory. */
-    "rootDir": "./src",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
-    "strict": true,                           /* Enable all strict type-checking options. */
-    "noImplicitAny": true,                    /* Raise error on expressions and declarations with an implied 'any' type. */
-    "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+    "target": "es6", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
+    "module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
+    "outDir": "./lib", /* Redirect output structure to the directory. */
+    "rootDir": "./src", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
+    "strict": true, /* Enable all strict type-checking options. */
+    "noImplicitAny": true, /* Raise error on expressions and declarations with an implied 'any' type. */
+    "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
   },
-  "exclude": ["node_modules", "**/*.test.ts"]
+  "exclude": [
+    "node_modules",
+    "**/*.test.ts",
+    "**/__mocks__"
+  ]
 }