4 files changed, 40 insertions, 11 deletions

diff --git a/config/build-common.js b/config/buildConstants.js
index ff5a218..4952907 100644
--- a/config/build-common.js
+++ b/config/buildConstants.js
@@ -1,6 +1,7 @@
 import { readFileSync } from 'fs';
-import { dirname, join } from 'path';
-import { fileURLToPath } from 'url';
+import { join } from 'path';
+
+import { fileURLToDirname } from './utils.js';
 
 const thisDir = fileURLToDirname(import.meta.url);
 
@@ -37,11 +38,3 @@ export const chrome = `chrome${chromeVersion}`;
 
 /** @type {string} */
 export const node = `node${nodeVersion}`;
-
-/**
- * @param {string} url
- * @returns {string}
- */
-export function fileURLToDirname(url) {
-  return dirname(fileURLToPath(url));
-}
diff --git a/config/esbuild-config.js b/config/esbuildConfig.js
index 5cef85f..05386b1 100644
--- a/config/esbuild-config.js
+++ b/config/esbuildConfig.js
@@ -1,4 +1,4 @@
-import { banner } from './build-common.js';
+import { banner } from './buildConstants.js';
 
 /** @type {string} */
 const mode = process.env.MODE || 'development';
diff --git a/config/jest.config.base.js b/config/jest.config.base.js
new file mode 100644
index 0000000..f265c1c
--- /dev/null
+++ b/config/jest.config.base.js
@@ -0,0 +1,26 @@
+import { join } from 'path';
+
+import { fileURLToDirname } from './utils.js';
+
+const dirname = fileURLToDirname(import.meta.url);
+
+/** @type {import('ts-jest').InitialOptionsTsJest} */
+export default {
+  preset: 'ts-jest/presets/default-esm',
+  globals: {
+    'ts-jest': {
+      useESM: true,
+    },
+  },
+  moduleNameMapper: {
+    '@sophie/(.+)': join(dirname, '../packages/$1/src/index.ts'),
+    '^(\\.{1,2}/.*)\\.js$': '$1',
+  },
+  resetMocks: true,
+  restoreMocks: true,
+  testEnvironment: 'node',
+  testPathIgnorePatterns: [
+    '/dist/',
+    '/node_modules/',
+  ],
+};
diff --git a/config/utils.js b/config/utils.js
new file mode 100644
index 0000000..d3e13d9
--- /dev/null
+++ b/config/utils.js
@@ -0,0 +1,10 @@
+import { dirname } from 'path';
+import { fileURLToPath } from 'url';
+
+/**
+ * @param {string} url
+ * @returns {string}
+ */
+export function fileURLToDirname(url) {
+  return dirname(fileURLToPath(url));
+}