diff --git a/tests/lib/extension/ConfigurationController.spec.ts b/tests/lib/extension/ConfigurationController.spec.ts
new file mode 100644
index 0000000..20e4577
--- /dev/null
+++ b/tests/lib/extension/ConfigurationController.spec.ts
@@ -0,0 +1,186 @@
+import ConfigurationController from "$lib/extension/ConfigurationController";
+import ChromeStorageArea from "$tests/mocks/ChromeStorageArea";
+import StorageHelper from "$lib/browser/StorageHelper";
+import { randomString } from "$tests/utils";
+
+describe('ConfigurationController', () => {
+  const mockedStorageArea = new ChromeStorageArea();
+  const mockedStorageHelper = new StorageHelper(mockedStorageArea);
+
+  beforeEach(() => {
+    mockedStorageArea.clear();
+  });
+
+  it('should read setting from the field inside the configuration object', async () => {
+    const name = randomString();
+    const field = randomString();
+    const value = randomString();
+
+    mockedStorageArea.insertMockedData({
+      [name]: {
+        [field]: value
+      }
+    });
+
+    const controller = new ConfigurationController(name, mockedStorageHelper);
+    const returnedValue = await controller.readSetting(field);
+
+    expect(returnedValue).toBe(value);
+  });
+
+  it('should return fallback value if configuration field does not exist', async () => {
+    const controller = new ConfigurationController(randomString(), mockedStorageHelper);
+    const fallbackValue = randomString();
+    const returnedValue = await controller.readSetting(randomString(), fallbackValue);
+
+    expect(returnedValue).toBe(fallbackValue);
+  });
+
+  it('should treat existing falsy values as existing values', async () => {
+    const name = randomString();
+
+    const falsyValuesStorage = [0, false, ''].reduce((record, value) => {
+      record[randomString()] = value;
+      return record;
+    }, {} as Record<string, any>);
+
+    mockedStorageArea.insertMockedData({
+      [name]: falsyValuesStorage
+    });
+
+    const controller = new ConfigurationController(name, mockedStorageHelper);
+
+    for (const fieldName of Object.keys(falsyValuesStorage)) {
+      const returnedValue = await controller.readSetting(fieldName, randomString());
+
+      expect(returnedValue).toBe(falsyValuesStorage[fieldName]);
+    }
+  });
+
+  it('should write data to storage', async () => {
+    const name = randomString();
+    const field = randomString();
+    const value = randomString();
+
+    const controller = new ConfigurationController(name, mockedStorageHelper);
+    await controller.writeSetting(field, value);
+
+    const expectedStructure = {
+      [name]: {
+        [field]: value,
+      }
+    };
+
+    expect(mockedStorageArea.mockedData).toEqual(expectedStructure);
+  });
+
+  it('should update existing object without touching other entries', async () => {
+    const name = randomString();
+    const existingField = randomString();
+    const existingValue = randomString();
+    const addedField = randomString();
+    const addedValue = randomString();
+
+    mockedStorageArea.insertMockedData({
+      [name]: {
+        [existingField]: existingValue,
+      }
+    });
+
+    const controller = new ConfigurationController(name, mockedStorageHelper);
+    await controller.writeSetting(addedField, addedValue);
+
+    const expectedStructure = {
+      [name]: {
+        [existingField]: existingValue,
+        [addedField]: addedValue,
+      }
+    }
+
+    expect(mockedStorageArea.mockedData).toEqual(expectedStructure);
+  });
+
+  it('should delete setting from storage', async () => {
+    const name = randomString();
+    const field = randomString();
+    const value = randomString();
+
+    mockedStorageArea.insertMockedData({
+      [name]: {
+        [field]: value
+      }
+    });
+
+    const controller = new ConfigurationController(name, mockedStorageHelper);
+    await controller.deleteSetting(field);
+
+    expect(mockedStorageArea.mockedData).toEqual({
+      [name]: {},
+    });
+  });
+
+  it('should return updated settings contents on changes', async () => {
+    const name = randomString();
+    const initialField = randomString();
+    const initialValue = randomString();
+
+    const addedField = randomString();
+    const addedValue = randomString();
+
+    const updatedInitialValue = randomString();
+    const receivedData: Record<string, string>[] = [];
+
+    mockedStorageArea.insertMockedData({
+      [name]: {
+        [initialField]: initialValue,
+      }
+    });
+
+    const controller = new ConfigurationController(name, mockedStorageHelper);
+    const subscriber = vi.fn((storageState: Record<string, string>) => {
+      receivedData.push(JSON.parse(JSON.stringify(storageState)));
+    });
+
+    controller.subscribeToChanges(subscriber);
+
+    await controller.writeSetting(addedField, addedValue);
+    await controller.writeSetting(initialField, updatedInitialValue);
+    await controller.deleteSetting(initialField);
+
+    expect(subscriber).toBeCalledTimes(3);
+
+    const expectedData: Record<string, string>[] = [
+      // First, initial data and added field are present
+      {
+        [initialField]: initialValue,
+        [addedField]: addedValue,
+      },
+      // Then we get new value on initial field
+      {
+        [initialField]: updatedInitialValue,
+        [addedField]: addedValue,
+      },
+      // And then the initial value is dropped
+      {
+        [addedField]: addedValue,
+      }
+    ];
+
+    expect(receivedData).toEqual(expectedData);
+  });
+
+  it('should stop listening once unsubscribe called', async () => {
+    const controller = new ConfigurationController(randomString(), mockedStorageHelper);
+    const subscriber = vi.fn();
+
+    const unsubscribe = controller.subscribeToChanges(subscriber);
+
+    await controller.writeSetting(randomString(), randomString());
+    expect(subscriber).toBeCalledTimes(1);
+
+    unsubscribe();
+    subscriber.mockReset();
+    await controller.writeSetting(randomString(), randomString())
+    expect(subscriber).not.toBeCalled();
+  });
+});
diff --git a/tests/utils.ts b/tests/utils.ts
new file mode 100644
index 0000000..61ac9a7
--- /dev/null
+++ b/tests/utils.ts
@@ -0,0 +1,7 @@
+export function randomString(): string {
+  return crypto.randomUUID();
+}
+
+export function copyValue<T>(object: T): T {
+  return JSON.parse(JSON.stringify(object));
+}