diff --git a/desktop/plugin-lib/package.json b/desktop/plugin-lib/package.json
index 354357ed1..ba382e5e8 100644
--- a/desktop/plugin-lib/package.json
+++ b/desktop/plugin-lib/package.json
@@ -24,6 +24,7 @@
     "flipper-test-utils": "0.45.0",
     "globby": "^10",
     "jest": "^25.1.0",
+    "mock-fs": "^4.12.0",
     "rimraf": "^3.0.2",
     "ts-jest": "^26.0.0",
     "ts-node": "^8",
diff --git a/desktop/plugin-lib/src/__tests__/pluginInstaller.node.ts b/desktop/plugin-lib/src/__tests__/pluginInstaller.node.ts
new file mode 100644
index 000000000..602c33885
--- /dev/null
+++ b/desktop/plugin-lib/src/__tests__/pluginInstaller.node.ts
@@ -0,0 +1,117 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import fs from 'fs-extra';
+import path from 'path';
+import mockfs from 'mock-fs';
+import {consoleMock} from 'flipper-test-utils';
+import {finishPendingPluginInstallations} from '../pluginInstaller';
+import {
+  pluginPendingInstallationDir,
+  pluginInstallationDir,
+} from '../pluginPaths';
+
+jest.mock('../pluginPaths', () => {
+  return {
+    pluginInstallationDir: path.join(
+      '',
+      'Users',
+      'mock',
+      '.flipper',
+      'thirdparty',
+    ),
+    pluginPendingInstallationDir: path.join(
+      '',
+      'Users',
+      'mock',
+      '.flipper',
+      'pending',
+    ),
+  };
+});
+
+describe('pluginInstaller', () => {
+  const realConsole = global.console;
+  global.console = consoleMock as any;
+
+  afterAll(() => {
+    global.console = realConsole;
+  });
+
+  beforeEach(() => {
+    mockfs({});
+  });
+
+  afterEach(() => {
+    mockfs.restore();
+  });
+
+  test('finish pending plugin installations', async () => {
+    mockfs({
+      [pluginPendingInstallationDir]: {
+        'flipper-plugin-test1': {
+          '1.2.0': {
+            'index.ts': '',
+            'package.json': '',
+          },
+        },
+        'flipper-plugin-test2': {
+          '0.3.0': {
+            'index.js': '<0.3.0>',
+            'package.json': '',
+          },
+          '0.2.0': {
+            'index.js': '<0.2.0>',
+            'package.json': '',
+          },
+        },
+      },
+    });
+
+    await finishPendingPluginInstallations();
+
+    expect(await fs.readdir(pluginInstallationDir)).toMatchInlineSnapshot(`
+      Array [
+        ".watchmanconfig",
+        "flipper-plugin-test1",
+        "flipper-plugin-test2",
+      ]
+    `);
+    expect(
+      await fs.readdir(
+        path.join(pluginInstallationDir, 'flipper-plugin-test1'),
+      ),
+    ).toMatchInlineSnapshot(`
+      Array [
+        "index.ts",
+        "package.json",
+      ]
+    `);
+    expect(
+      await fs.readdir(
+        path.join(pluginInstallationDir, 'flipper-plugin-test2'),
+      ),
+    ).toMatchInlineSnapshot(`
+      Array [
+        "index.js",
+        "package.json",
+      ]
+    `);
+    expect(
+      (
+        await fs.readFile(
+          path.join(pluginInstallationDir, 'flipper-plugin-test2', 'index.js'),
+        )
+      ).toString(),
+    ).toBe('<0.3.0>');
+    expect(
+      await fs.readdir(pluginPendingInstallationDir),
+    ).toMatchInlineSnapshot(`Array []`);
+  });
+});
diff --git a/desktop/plugin-lib/src/pluginInstaller.ts b/desktop/plugin-lib/src/pluginInstaller.ts
index d45ad1f0d..931364378 100644
--- a/desktop/plugin-lib/src/pluginInstaller.ts
+++ b/desktop/plugin-lib/src/pluginInstaller.ts
@@ -253,7 +253,7 @@ export async function finishPendingPluginInstallations() {
       pluginInstallationDir,
       '.watchmanconfig',
     );
-    if (await fs.pathExists(watchmanConfigPath)) {
+    if (!(await fs.pathExists(watchmanConfigPath))) {
       await fs.writeFile(watchmanConfigPath, '{}');
     }
     const pendingPlugins = await fs.readdir(pluginPendingInstallationDir);