diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 0000000..4cc0a8e
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,77 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  test:
+    if: "!contains(github.event.head_commit.message, '[skip ci]')"
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 12
+      - uses: actions/cache@v2
+        with:
+          path: ~/.pnpm-store
+          key: ${{ runner.os }}-build-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-build-
+      - run: |
+          npm -g install pnpm@5.16
+          pnpm set verify-store-integrity false
+      - run: pnpm install
+      - run: pnpm run test:coverage
+      - uses: codecov/codecov-action@v1
+      - run: mv "$(pnpm pack | tail -n 1)" pkg.tgz
+      - uses: actions/upload-artifact@v2
+        with:
+          name: package-art
+          path: pkg.tgz
+  test_example:
+    needs: test
+    runs-on: ubuntu-20.04
+    defaults:
+      run:
+        working-directory: example
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 12
+      - uses: actions/download-artifact@v2
+        with:
+          name: package-art
+          path: example
+      - run: npm install pkg.tgz --only=development --no-package-lock
+      - uses: actions/cache@v2
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-build-example-${{ hashFiles('**/example/package.json') }}
+          restore-keys: |
+            ${{ runner.os }}-build-example-npm-
+      - run: npm install
+      - run: npm run build -- --prefix-paths
+      - if: github.event_name == 'push'
+        uses: actions/upload-artifact@v2
+        with:
+          name: example-art
+          path: example/public
+  deploy_example:
+    if: github.event_name == 'push'
+    needs: test_example
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/download-artifact@v2
+        with:
+          name: example-art
+          path: public
+      - uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: public
+          force_orphan: true
diff --git a/src/__tests__/__fixtures__/pluginOptionsSchema.js b/src/__tests__/__fixtures__/pluginOptionsSchema.js
new file mode 100644
index 0000000..9b8bec6
--- /dev/null
+++ b/src/__tests__/__fixtures__/pluginOptionsSchema.js
@@ -0,0 +1,39 @@
+export default [
+  {
+    title: 'should invalidate unknown options',
+    options: {
+      unknown: 5,
+      foo: {
+        bar: true,
+      },
+    }
+  },
+  {
+    title: 'should invalidate options with incorrect data types',
+    options: {
+      enabled: 5,
+      report: [],
+      purgecss: {
+        defaultExtractor: '',
+        safelist: true,
+        blocklist: [{}]
+      },
+    }
+  },
+  {
+    title: 'should validate correct options',
+    options: {
+      enabled: true,
+      report: false,
+      reportConsole: true,
+      purgecss: {
+        allowSymbols: false,
+        rejected: false,
+        defaultExtractor: s => s,
+        fontFace: false,
+        keyframes: true,
+        variables: true
+      }
+    }
+  }
+]
diff --git a/src/__tests__/__snapshots__/bootstrap.js.snap b/src/__tests__/__snapshots__/bootstrap.js.snap
new file mode 100644
index 0000000..70ef4f2
--- /dev/null
+++ b/src/__tests__/__snapshots__/bootstrap.js.snap
@@ -0,0 +1,39 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`onPreBootstrap correctly initializes custom options 1`] = `
+Object {
+  "_pathPrefix": "",
+  "_plugin": "gatsby-plugin-postbuild",
+  "_public": "/virtual/project/public",
+  "_root": "/virtual/project",
+  "enabled": true,
+  "purgecss": Object {
+    "allowSymbols": true,
+    "fontFace": false,
+    "keyframes": false,
+    "rejected": false,
+    "variables": false,
+  },
+  "report": false,
+  "reportConsole": true,
+}
+`;
+
+exports[`onPreBootstrap correctly initializes default options 1`] = `
+Object {
+  "_pathPrefix": "",
+  "_plugin": "gatsby-plugin-postbuild",
+  "_public": "/virtual/project/public",
+  "_root": "/virtual/project",
+  "enabled": true,
+  "purgecss": Object {
+    "allowSymbols": false,
+    "fontFace": false,
+    "keyframes": false,
+    "rejected": true,
+    "variables": false,
+  },
+  "report": true,
+  "reportConsole": true,
+}
+`;
diff --git a/src/__tests__/__snapshots__/pluginOptionsSchema.js.snap b/src/__tests__/__snapshots__/pluginOptionsSchema.js.snap
new file mode 100644
index 0000000..a09f36b
--- /dev/null
+++ b/src/__tests__/__snapshots__/pluginOptionsSchema.js.snap
@@ -0,0 +1,26 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`pluginOptionsSchema should invalidate options with incorrect data types 1`] = `false`;
+
+exports[`pluginOptionsSchema should invalidate options with incorrect data types 2`] = `
+Array [
+  "\\"enabled\\" must be a boolean",
+  "\\"report\\" must be a boolean",
+  "\\"purgecss.defaultExtractor\\" must be of type function",
+  "\\"purgecss.safelist\\" must be one of [object, array]",
+  "\\"purgecss.blocklist[0]\\" must be a string",
+]
+`;
+
+exports[`pluginOptionsSchema should invalidate unknown options 1`] = `false`;
+
+exports[`pluginOptionsSchema should invalidate unknown options 2`] = `
+Array [
+  "\\"unknown\\" is not allowed",
+  "\\"foo\\" is not allowed",
+]
+`;
+
+exports[`pluginOptionsSchema should validate correct options 1`] = `true`;
+
+exports[`pluginOptionsSchema should validate correct options 2`] = `Array []`;
diff --git a/src/__tests__/bootstrap.js b/src/__tests__/bootstrap.js
new file mode 100644
index 0000000..b41a097
--- /dev/null
+++ b/src/__tests__/bootstrap.js
@@ -0,0 +1,22 @@
+import fs from 'fs'
+import { options } from '../util'
+import { mountOptions } from '../../test/utils'
+jest.mock('fs')
+
+describe('onPreBootstrap', () => {
+  it('correctly initializes default options', () => {
+    expect(() => mountOptions()).not.toThrow()
+    expect(options).toMatchSnapshot()
+  })
+
+  it('correctly initializes custom options', () => {
+    expect(() => mountOptions({
+      report: false,
+      purgecss: {
+        allowSymbols: true,
+        rejected: false
+      }
+    })).not.toThrow()
+    expect(options).toMatchSnapshot()
+  })
+})
diff --git a/src/__tests__/pluginOptionsSchema.js b/src/__tests__/pluginOptionsSchema.js
new file mode 100644
index 0000000..a4a643b
--- /dev/null
+++ b/src/__tests__/pluginOptionsSchema.js
@@ -0,0 +1,17 @@
+import { testPluginOptionsSchema } from 'gatsby-plugin-utils'
+import { pluginOptionsSchema } from '../'
+import testCases from './__fixtures__/pluginOptionsSchema'
+
+describe('pluginOptionsSchema', () => {
+  for (const { title, options } of testCases) {
+    it(title, async () => {
+      const { isValid, errors } = await testPluginOptionsSchema(
+        pluginOptionsSchema,
+        options
+      )
+
+      expect(isValid).toMatchSnapshot()
+      expect(errors).toMatchSnapshot()
+    })
+  }
+})