diff --git a/.travis.yml b/.travis.yml
index 247ab71..775ad1f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,17 @@
 language: node_js
+
 node_js:
   - "10"
+
 branches:
   only:
     - master
+
+jobs:
+  include:
+    - install: npm ci
+    - install: npm install --no-shrinkwrap
+
+before_script:
+  - npm ls css-loader
+  - npm ls typescript
diff --git a/package-lock.json b/package-lock.json
index 079f3db..b3a0826 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1950,7 +1950,68 @@
       }
     },
     "css-loader": {
-      "version": "3.6.0",
+      "version": "4.2.1",
+      "resolved": "https://registry.npmjs.org/css-loader/-/css-loader-4.2.1.tgz",
+      "integrity": "sha512-MoqmF1if7Z0pZIEXA4ZF9PgtCXxWbfzfJM+3p+OYfhcrwcqhaCRb74DSnfzRl7e024xEiCRn5hCvfUbTf2sgFA==",
+      "dev": true,
+      "requires": {
+        "camelcase": "^6.0.0",
+        "cssesc": "^3.0.0",
+        "icss-utils": "^4.1.1",
+        "loader-utils": "^2.0.0",
+        "normalize-path": "^3.0.0",
+        "postcss": "^7.0.32",
+        "postcss-modules-extract-imports": "^2.0.0",
+        "postcss-modules-local-by-default": "^3.0.3",
+        "postcss-modules-scope": "^2.2.0",
+        "postcss-modules-values": "^3.0.0",
+        "postcss-value-parser": "^4.1.0",
+        "schema-utils": "^2.7.0",
+        "semver": "^7.3.2"
+      },
+      "dependencies": {
+        "camelcase": {
+          "version": "6.0.0",
+          "resolved": "https://registry.npmjs.org/camelcase/-/camelcase-6.0.0.tgz",
+          "integrity": "sha512-8KMDF1Vz2gzOq54ONPJS65IvTUaB1cHJ2DMM7MbPmLZljDH1qpzzLsWdiN9pHh6qvkRVDTi/07+eNGch/oLU4w==",
+          "dev": true
+        },
+        "emojis-list": {
+          "version": "3.0.0",
+          "resolved": "https://registry.npmjs.org/emojis-list/-/emojis-list-3.0.0.tgz",
+          "integrity": "sha512-/kyM18EfinwXZbno9FyUGeFh87KC8HRQBQGildHZbEuRyWFOmv1U10o9BBp8XVZDVNNuQKyIGIu5ZYAAXJ0V2Q==",
+          "dev": true
+        },
+        "json5": {
+          "version": "2.1.3",
+          "resolved": "https://registry.npmjs.org/json5/-/json5-2.1.3.tgz",
+          "integrity": "sha512-KXPvOm8K9IJKFM0bmdn8QXh7udDh1g/giieX0NLCaMnb4hEiVFqnop2ImTXCc5e0/oHz3LTqmHGtExn5hfMkOA==",
+          "dev": true,
+          "requires": {
+            "minimist": "^1.2.5"
+          }
+        },
+        "loader-utils": {
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/loader-utils/-/loader-utils-2.0.0.tgz",
+          "integrity": "sha512-rP4F0h2RaWSvPEkD7BLDFQnvSf+nK+wr3ESUjNTyAGobqrijmW92zc+SO6d4p4B1wh7+B/Jg1mkQe5NYUEHtHQ==",
+          "dev": true,
+          "requires": {
+            "big.js": "^5.2.2",
+            "emojis-list": "^3.0.0",
+            "json5": "^2.1.2"
+          }
+        },
+        "semver": {
+          "version": "7.3.2",
+          "resolved": "https://registry.npmjs.org/semver/-/semver-7.3.2.tgz",
+          "integrity": "sha512-OrOb32TeeambH6UrhtShmF7CRDqhL6/5XpPNp2DuRH6+9QLw/orhp72j87v8Qa1ScDkvrrBNpZcDejAirJmfXQ==",
+          "dev": true
+        }
+      }
+    },
+    "css-loader3": {
+      "version": "npm:css-loader@3.6.0",
       "resolved": "https://registry.npmjs.org/css-loader/-/css-loader-3.6.0.tgz",
       "integrity": "sha512-M5lSukoWi1If8dhQAUCvj4H8vUt3vOnwbQBH9DdTm/s4Ym2B/3dPMtYZeJmq7Q3S3Pa+I94DcZ7pc9bP14cWIQ==",
       "dev": true,
diff --git a/package.json b/package.json
index 3d2a857..1141db7 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,8 @@
   },
   "devDependencies": {
     "@types/jest": "^24.0.23",
-    "css-loader": "^3.1.0",
+    "css-loader": "*",
+    "css-loader3": "npm:css-loader@^3.1.0",
     "eslint": "4.18.2",
     "eslint-config-prettier": "^6.0.0",
     "jest": "^24.9.0",
diff --git a/src/index.js b/src/index.js
index 9f2af79..19febfb 100644
--- a/src/index.js
+++ b/src/index.js
@@ -3,7 +3,7 @@ const {
   filenameToPascalCase,
   filenameToTypingsFilename,
   getCssModuleKeys,
-  generateGenericExportInterface
+  generateGenericExportInterface,
 } = require("./utils");
 const persist = require("./persist");
 const verify = require("./verify");
@@ -16,39 +16,38 @@ const schema = {
     eol: {
       description:
         "Newline character to be used in generated d.ts files. Uses OS default. This option is overridden by the formatter option.",
-      type: "string"
+      type: "string",
     },
     banner: {
       description: "To add a 'banner' prefix to each generated `*.d.ts` file",
-      type: "string"
+      type: "string",
     },
     formatter: {
       description:
         "Possible options: none and prettier (requires prettier package installed). Defaults to prettier if `prettier` module can be resolved",
-      enum: ["prettier", "none"]
+      enum: ["prettier", "none"],
     },
     disableLocalsExport: {
-      description:
-        "Disable the use of locals export. Defaults to `false`",
-      type: "boolean"
+      description: "Disable the use of locals export. Defaults to `false`",
+      type: "boolean",
     },
     verifyOnly: {
       description:
         "Validate generated `*.d.ts` files and fail if an update is needed (useful in CI). Defaults to `false`",
-      type: "boolean"
-    }
+      type: "boolean",
+    },
   },
-  additionalProperties: false
+  additionalProperties: false,
 };
 
 /** @type {any} */
 const configuration = {
   name: "typings-for-css-modules-loader",
-  baseDataPath: "options"
+  baseDataPath: "options",
 };
 
 /** @type {((this: import('webpack').loader.LoaderContext, ...args: any[]) => void) & {pitch?: import('webpack').loader.Loader['pitch']}} */
-module.exports = function(content, ...args) {
+module.exports = function (content, ...args) {
   const options = getOptions(this) || {};
 
   validateOptions(schema, options, configuration);
@@ -58,9 +57,12 @@ module.exports = function(content, ...args) {
   }
 
   // let's only check `exports.locals` for keys to avoid getting keys from the sourcemap when it's enabled
-  const cssModuleKeys = getCssModuleKeys(
-    content.substring(content.indexOf("exports.locals"))
-  );
+  // if we cannot find locals, then the module only contains global styles
+  const indexOfLocals = content.indexOf(".locals");
+  const cssModuleKeys =
+    indexOfLocals === -1
+      ? []
+      : getCssModuleKeys(content.substring(indexOfLocals));
 
   /** @type {any} */
   const callback = this.async();
@@ -85,14 +87,14 @@ module.exports = function(content, ...args) {
   );
 
   applyFormattingAndOptions(cssModuleDefinition, options)
-    .then(output => {
+    .then((output) => {
       if (options.verifyOnly === true) {
         return verify(cssModuleInterfaceFilename, output);
       } else {
         persist(cssModuleInterfaceFilename, output);
       }
     })
-    .catch(err => {
+    .catch((err) => {
       this.emitError(err);
     })
     .then(successfulCallback);
@@ -132,7 +134,7 @@ async function applyPrettier(input) {
   const prettier = require("prettier");
 
   const config = await prettier.resolveConfig("./", {
-    editorconfig: true
+    editorconfig: true,
   });
 
   return prettier.format(
diff --git a/src/utils.js b/src/utils.js
index 17a0c6b..3454110 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -6,7 +6,7 @@ const camelCase = require("camelcase");
  * @param {string} content
  * @returns {string[]}
  */
-const getCssModuleKeys = content => {
+const getCssModuleKeys = (content) => {
   const keyRegex = /"([\w-]+)":/g;
   let match;
   const cssModuleKeys = [];
@@ -22,7 +22,7 @@ const getCssModuleKeys = content => {
 /**
  * @param {string} filename
  */
-const filenameToPascalCase = filename => {
+const filenameToPascalCase = (filename) => {
   return camelCase(path.basename(filename), { pascalCase: true });
 };
 
@@ -33,11 +33,11 @@ const filenameToPascalCase = filename => {
 const cssModuleToTypescriptInterfaceProperties = (cssModuleKeys, indent) => {
   return [...cssModuleKeys]
     .sort()
-    .map(key => `${indent || ""}'${key}': string;`)
+    .map((key) => `${indent || ""}'${key}': string;`)
     .join("\n");
 };
 
-const filenameToTypingsFilename = filename => {
+const filenameToTypingsFilename = (filename) => {
   const dirName = path.dirname(filename);
   const baseName = path.basename(filename);
   return path.join(dirName, `${baseName}.d.ts`);
@@ -47,12 +47,18 @@ const filenameToTypingsFilename = filename => {
  * @param {string[]} cssModuleKeys
  * @param {string} pascalCaseFileName
  */
-const generateGenericExportInterface = (cssModuleKeys, pascalCaseFileName, disableLocalsExport) => {
+const generateGenericExportInterface = (
+  cssModuleKeys,
+  pascalCaseFileName,
+  disableLocalsExport
+) => {
   const interfaceName = `I${pascalCaseFileName}`;
   const moduleName = `${pascalCaseFileName}Module`;
   const namespaceName = `${pascalCaseFileName}Namespace`;
 
-  const localsExportType = disableLocalsExport ? `` : ` & {
+  const localsExportType = disableLocalsExport
+    ? ``
+    : ` & {
   /** WARNING: Only available when \`css-loader\` is used without \`style-loader\` or \`mini-css-extract-plugin\` */
   locals: ${namespaceName}.${interfaceName};
 }`;
@@ -76,5 +82,5 @@ module.exports = {
   getCssModuleKeys,
   filenameToPascalCase,
   filenameToTypingsFilename,
-  generateGenericExportInterface
+  generateGenericExportInterface,
 };
diff --git a/src/verify.js b/src/verify.js
index 65d1c7a..a584d0e 100644
--- a/src/verify.js
+++ b/src/verify.js
@@ -1,6 +1,6 @@
 // @ts-check
-const fs = require('fs');
-const util = require('util');
+const fs = require("fs");
+const util = require("util");
 const fsStat = util.promisify(fs.stat);
 const fsReadFile = util.promisify(fs.readFile);
 /**
@@ -10,18 +10,23 @@ const fsReadFile = util.promisify(fs.readFile);
  */
 module.exports = async (filename, content) => {
   const fileExists = await fsStat(filename)
-    .then(() => true).catch(() => false);
+    .then(() => true)
+    .catch(() => false);
 
   if (!fileExists) {
-    throw new Error(`Verification failed: Generated typings for css-module file '${filename}' is not found. ` +
-      "It typically happens when the generated typings were not committed.");
+    throw new Error(
+      `Verification failed: Generated typings for css-module file '${filename}' is not found. ` +
+        "It typically happens when the generated typings were not committed."
+    );
   }
 
-  const existingFileContent = await fsReadFile(filename, 'utf-8');
+  const existingFileContent = await fsReadFile(filename, "utf-8");
 
   // let's not fail the build if there are whitespace changes only
   if (existingFileContent.replace(/\s+/g, "") !== content.replace(/\s+/g, "")) {
-    throw new Error(`Verification failed: Generated typings for css-modules file '${filename}' is out of date. ` +
-      "It typically happens when the up-to-date generated typings are not committed.");
+    throw new Error(
+      `Verification failed: Generated typings for css-modules file '${filename}' is out of date. ` +
+        "It typically happens when the up-to-date generated typings are not committed."
+    );
   }
 };
diff --git a/test/__snapshots__/index.test.js.snap b/test/__snapshots__/index.test.js.snap
index edbbb14..069a0a3 100644
--- a/test/__snapshots__/index.test.js.snap
+++ b/test/__snapshots__/index.test.js.snap
@@ -1,6 +1,6 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`default options 1`] = `
+exports[`css-loader@3 default options 1`] = `
 "declare namespace ExampleCssNamespace {
   export interface IExampleCss {
     \\"bar-baz\\": string;
@@ -18,7 +18,7 @@ export = ExampleCssModule;
 "
 `;
 
-exports[`localsConvention asIs 1`] = `
+exports[`css-loader@3 localsConvention asIs 1`] = `
 "declare namespace ExampleCssNamespace {
   export interface IExampleCss {
     \\"bar-baz\\": string;
@@ -36,7 +36,7 @@ export = ExampleCssModule;
 "
 `;
 
-exports[`localsConvention camelCase 1`] = `
+exports[`css-loader@3 localsConvention camelCase 1`] = `
 "declare namespace ExampleCssNamespace {
   export interface IExampleCss {
     \\"bar-baz\\": string;
@@ -55,7 +55,7 @@ export = ExampleCssModule;
 "
 `;
 
-exports[`with banner 1`] = `
+exports[`css-loader@3 with banner 1`] = `
 "// autogenerated by typings-for-css-modules-loader
 declare namespace ExampleCssNamespace {
   export interface IExampleCss {
@@ -74,7 +74,7 @@ export = ExampleCssModule;
 "
 `;
 
-exports[`with locals export disabled 1`] = `
+exports[`css-loader@3 with locals export disabled 1`] = `
 "declare namespace ExampleCssNamespace {
   export interface IExampleCss {
     \\"bar-baz\\": string;
@@ -89,7 +89,7 @@ export = ExampleCssModule;
 "
 `;
 
-exports[`with no formatter 1`] = `
+exports[`css-loader@3 with no formatter 1`] = `
 "declare namespace ExampleCssNamespace {
   export interface IExampleCss {
     'bar-baz': string;
@@ -106,7 +106,7 @@ declare const ExampleCssModule: ExampleCssNamespace.IExampleCss & {
 export = ExampleCssModule;"
 `;
 
-exports[`with prettier 1`] = `
+exports[`css-loader@3 with prettier 1`] = `
 "declare namespace ExampleCssNamespace {
   export interface IExampleCss {
     \\"bar-baz\\": string;
@@ -124,7 +124,149 @@ export = ExampleCssModule;
 "
 `;
 
-exports[`with sourcemap 1`] = `
+exports[`css-loader@3 with sourcemap 1`] = `
+"declare namespace ExampleCssNamespace {
+  export interface IExampleCss {
+    \\"bar-baz\\": string;
+    composed: string;
+    foo: string;
+  }
+}
+
+declare const ExampleCssModule: ExampleCssNamespace.IExampleCss & {
+  /** WARNING: Only available when \`css-loader\` is used without \`style-loader\` or \`mini-css-extract-plugin\` */
+  locals: ExampleCssNamespace.IExampleCss;
+};
+
+export = ExampleCssModule;
+"
+`;
+
+exports[`css-loader@latest default options 1`] = `
+"declare namespace ExampleCssNamespace {
+  export interface IExampleCss {
+    \\"bar-baz\\": string;
+    composed: string;
+    foo: string;
+  }
+}
+
+declare const ExampleCssModule: ExampleCssNamespace.IExampleCss & {
+  /** WARNING: Only available when \`css-loader\` is used without \`style-loader\` or \`mini-css-extract-plugin\` */
+  locals: ExampleCssNamespace.IExampleCss;
+};
+
+export = ExampleCssModule;
+"
+`;
+
+exports[`css-loader@latest localsConvention asIs 1`] = `
+"declare namespace ExampleCssNamespace {
+  export interface IExampleCss {
+    \\"bar-baz\\": string;
+    composed: string;
+    foo: string;
+  }
+}
+
+declare const ExampleCssModule: ExampleCssNamespace.IExampleCss & {
+  /** WARNING: Only available when \`css-loader\` is used without \`style-loader\` or \`mini-css-extract-plugin\` */
+  locals: ExampleCssNamespace.IExampleCss;
+};
+
+export = ExampleCssModule;
+"
+`;
+
+exports[`css-loader@latest localsConvention camelCase 1`] = `
+"declare namespace ExampleCssNamespace {
+  export interface IExampleCss {
+    \\"bar-baz\\": string;
+    barBaz: string;
+    composed: string;
+    foo: string;
+  }
+}
+
+declare const ExampleCssModule: ExampleCssNamespace.IExampleCss & {
+  /** WARNING: Only available when \`css-loader\` is used without \`style-loader\` or \`mini-css-extract-plugin\` */
+  locals: ExampleCssNamespace.IExampleCss;
+};
+
+export = ExampleCssModule;
+"
+`;
+
+exports[`css-loader@latest with banner 1`] = `
+"// autogenerated by typings-for-css-modules-loader
+declare namespace ExampleCssNamespace {
+  export interface IExampleCss {
+    \\"bar-baz\\": string;
+    composed: string;
+    foo: string;
+  }
+}
+
+declare const ExampleCssModule: ExampleCssNamespace.IExampleCss & {
+  /** WARNING: Only available when \`css-loader\` is used without \`style-loader\` or \`mini-css-extract-plugin\` */
+  locals: ExampleCssNamespace.IExampleCss;
+};
+
+export = ExampleCssModule;
+"
+`;
+
+exports[`css-loader@latest with locals export disabled 1`] = `
+"declare namespace ExampleCssNamespace {
+  export interface IExampleCss {
+    \\"bar-baz\\": string;
+    composed: string;
+    foo: string;
+  }
+}
+
+declare const ExampleCssModule: ExampleCssNamespace.IExampleCss;
+
+export = ExampleCssModule;
+"
+`;
+
+exports[`css-loader@latest with no formatter 1`] = `
+"declare namespace ExampleCssNamespace {
+  export interface IExampleCss {
+    'bar-baz': string;
+    'composed': string;
+    'foo': string;
+  }
+}
+
+declare const ExampleCssModule: ExampleCssNamespace.IExampleCss & {
+  /** WARNING: Only available when \`css-loader\` is used without \`style-loader\` or \`mini-css-extract-plugin\` */
+  locals: ExampleCssNamespace.IExampleCss;
+};
+
+export = ExampleCssModule;"
+`;
+
+exports[`css-loader@latest with prettier 1`] = `
+"declare namespace ExampleCssNamespace {
+  export interface IExampleCss {
+    \\"bar-baz\\": string;
+    composed: string;
+    foo: string;
+  }
+}
+
+declare const ExampleCssModule: ExampleCssNamespace.IExampleCss & {
+  /** WARNING: Only available when \`css-loader\` is used without \`style-loader\` or \`mini-css-extract-plugin\` */
+  locals: ExampleCssNamespace.IExampleCss;
+};
+
+export = ExampleCssModule;
+"
+`;
+
+exports[`css-loader@latest with sourcemap 1`] = `
 "declare namespace ExampleCssNamespace {
   export interface IExampleCss {
     \\"bar-baz\\": string;
diff --git a/test/example-no-locals.css b/test/example-no-locals.css
new file mode 100644
index 0000000..6380c4c
--- /dev/null
+++ b/test/example-no-locals.css
@@ -0,0 +1,3 @@
+div {
+  background: red;
+}
diff --git a/test/index.test.js b/test/index.test.js
index 8b2dca4..d2032d1 100644
--- a/test/index.test.js
+++ b/test/index.test.js
@@ -9,168 +9,330 @@ beforeEach(() => {
   jest.mock("../src/verify");
 });
 
-it("default options", async () => {
-  await runTest();
+describe("css-loader@latest", () => {
+  const runTest = createTestRunner();
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(1);
-  expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  it("default options", async () => {
+    await runTest();
 
-  const verifyMock = jest.requireMock("../src/verify");
-  expect(verifyMock).toBeCalledTimes(0);
-});
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
 
-it("with sourcemap", async () => {
-  await runTest({
-    cssLoaderOptions: {
-      sourceMap: true
-    }
+    const verifyMock = jest.requireMock("../src/verify");
+    expect(verifyMock).toBeCalledTimes(0);
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(1);
-  expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
-});
+  it("with sourcemap", async () => {
+    await runTest({
+      cssLoaderOptions: {
+        sourceMap: true,
+      },
+    });
 
-it("no modules", async () => {
-  await runTest({
-    cssLoaderOptions: {
-      modules: false
-    }
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(0);
-});
+  it("no locals in output", async () => {
+    await runTest({
+      fileName: "./example-no-locals.css",
+      cssLoaderOptions: {
+        sourceMap: true,
+      },
+    });
 
-it("localsConvention asIs", async () => {
-  await runTest({
-    cssLoaderOptions: {
-      localsConvention: "asIs"
-    }
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(0);
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(1);
-  expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
-});
+  it("no modules", async () => {
+    await runTest({
+      cssLoaderOptions: {
+        modules: false,
+      },
+    });
 
-it("localsConvention camelCase", async () => {
-  await runTest({
-    cssLoaderOptions: {
-      localsConvention: "camelCase"
-    }
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(0);
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(1);
-  expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
-});
+  it("localsConvention asIs", async () => {
+    await runTest({
+      cssLoaderOptions: {
+        modules: {
+          exportLocalsConvention: "asIs",
+        },
+      },
+    });
 
-it("with prettier", async () => {
-  await runTest({
-    options: {
-      formatter: "prettier"
-    }
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(1);
-  expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
-});
+  it("localsConvention camelCase", async () => {
+    await runTest({
+      cssLoaderOptions: {
+        modules: {
+          exportLocalsConvention: "camelCase",
+        },
+      },
+    });
 
-it("with no formatter", async () => {
-  await runTest({
-    options: {
-      formatter: "none"
-    }
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(1);
-  expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
-});
+  it("with prettier", async () => {
+    await runTest({
+      options: {
+        formatter: "prettier",
+      },
+    });
 
-it("with banner", async () => {
-  await runTest({
-    options: {
-      banner: "// autogenerated by typings-for-css-modules-loader"
-    }
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(1);
-  expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
-});
+  it("with no formatter", async () => {
+    await runTest({
+      options: {
+        formatter: "none",
+      },
+    });
 
-it("with locals export disabled", async () => {
-  await runTest({
-    options: {
-      disableLocalsExport: true
-    }
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(1);
-  expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
-});
+  it("with banner", async () => {
+    await runTest({
+      options: {
+        banner: "// autogenerated by typings-for-css-modules-loader",
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  });
+
+  it("with locals export disabled", async () => {
+    await runTest({
+      options: {
+        disableLocalsExport: true,
+      },
+    });
 
-it("with verify only", async () => {
-  await runTest({
-    options: {
-      verifyOnly: true
-    }
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
   });
 
-  const persistMock = jest.requireMock("../src/persist");
-  expect(persistMock).toBeCalledTimes(0);
+  it("with verify only", async () => {
+    await runTest({
+      options: {
+        verifyOnly: true,
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(0);
 
-  const verifyMock = jest.requireMock("../src/verify");
-  expect(verifyMock).toBeCalledTimes(1);
+    const verifyMock = jest.requireMock("../src/verify");
+    expect(verifyMock).toBeCalledTimes(1);
+  });
 });
 
-async function runTest({ options = {}, cssLoaderOptions = {} } = {}) {
-  const compiler = webpack({
-    entry: path.resolve(__dirname, "./example.css"),
-    target: "node",
-    module: {
-      rules: [
-        {
-          test: /\.css$/,
-          use: [
-            {
-              loader: require.resolve("../src/index.js"),
-              options
-            },
-            {
-              loader: "css-loader",
-              options: Object.assign(
-                {
-                  modules: true
-                },
-                cssLoaderOptions
-              )
-            }
-          ]
-        }
-      ]
-    },
-    mode: "none"
+describe("css-loader@3", () => {
+  const runTest = createTestRunner("css-loader3");
+
+  it("default options", async () => {
+    await runTest();
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+
+    const verifyMock = jest.requireMock("../src/verify");
+    expect(verifyMock).toBeCalledTimes(0);
+  });
+
+  it("with sourcemap", async () => {
+    await runTest({
+      cssLoaderOptions: {
+        sourceMap: true,
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  });
+
+  it("no locals in output", async () => {
+    await runTest({
+      fileName: "./example-no-locals.css",
+      cssLoaderOptions: {
+        sourceMap: true,
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(0);
   });
 
-  compiler.outputFileSystem = new memoryfs();
+  it("no modules", async () => {
+    await runTest({
+      cssLoaderOptions: {
+        modules: false,
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(0);
+  });
+
+  it("localsConvention asIs", async () => {
+    await runTest({
+      cssLoaderOptions: {
+        localsConvention: "asIs",
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  });
+
+  it("localsConvention camelCase", async () => {
+    await runTest({
+      cssLoaderOptions: {
+        localsConvention: "camelCase",
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  });
+
+  it("with prettier", async () => {
+    await runTest({
+      options: {
+        formatter: "prettier",
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  });
+
+  it("with no formatter", async () => {
+    await runTest({
+      options: {
+        formatter: "none",
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  });
+
+  it("with banner", async () => {
+    await runTest({
+      options: {
+        banner: "// autogenerated by typings-for-css-modules-loader",
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  });
+
+  it("with locals export disabled", async () => {
+    await runTest({
+      options: {
+        disableLocalsExport: true,
+      },
+    });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(1);
+    expect(persistMock.mock.calls[0][1]).toMatchSnapshot();
+  });
 
-  /** @type {webpack.Stats} */
-  const stats = await new Promise((resolve, reject) => {
-    compiler.run((err, stats) => {
-      if (err) {
-        reject(err);
-      } else {
-        resolve(stats);
-      }
+  it("with verify only", async () => {
+    await runTest({
+      options: {
+        verifyOnly: true,
+      },
     });
+
+    const persistMock = jest.requireMock("../src/persist");
+    expect(persistMock).toBeCalledTimes(0);
+
+    const verifyMock = jest.requireMock("../src/verify");
+    expect(verifyMock).toBeCalledTimes(1);
   });
+});
+
+function createTestRunner(cssLoaderModule = "css-loader") {
+  return async ({
+    fileName = "./example.css",
+    options = {},
+    cssLoaderOptions = {},
+  } = {}) => {
+    const compiler = webpack({
+      entry: path.resolve(__dirname, fileName),
+      target: "node",
+      module: {
+        rules: [
+          {
+            test: /\.css$/,
+            use: [
+              {
+                loader: require.resolve("../src/index.js"),
+                options,
+              },
+              {
+                loader: cssLoaderModule,
+                options: Object.assign(
+                  {
+                    modules: true,
+                  },
+                  cssLoaderOptions
+                ),
+              },
+            ],
+          },
+        ],
+      },
+      mode: "none",
+    });
+
+    compiler.outputFileSystem = new memoryfs();
+
+    /** @type {webpack.Stats} */
+    const stats = await new Promise((resolve, reject) => {
+      compiler.run((err, stats) => {
+        if (err) {
+          reject(err);
+        } else {
+          resolve(stats);
+        }
+      });
+    });
 
-  const s = stats.toJson();
-  expect(s.errors).toHaveLength(0);
+    const s = stats.toJson();
+    expect(s.errors).toHaveLength(0);
+  };
 }
diff --git a/test/utils.test.js b/test/utils.test.js
index 4ad272c..8170bdd 100644
--- a/test/utils.test.js
+++ b/test/utils.test.js
@@ -37,18 +37,18 @@ describe("getCssModuleKeys", () => {
   it("CSS module with one class", () => {
     const content = `exports.locals = {
       "test": "test"
-    };`
+    };`;
     const actual = getCssModuleKeys(content);
-    expect(actual).toEqual(['test']);
+    expect(actual).toEqual(["test"]);
   });
 
   it("CSS module with multiple classes", () => {
     const content = `exports.locals = {
       "test1": "test1",
       "test2": "test2"
-    };`
+    };`;
     const actual = getCssModuleKeys(content);
-    expect(actual).toEqual(['test1', 'test2']);
+    expect(actual).toEqual(["test1", "test2"]);
   });
 
   it("CSS module with :root pseudo-class only", () => {