diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index b8b7c38e4..2f114e9f0 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -561,10 +561,15 @@ module.exports = class MetamaskController extends EventEmitter {
         return accounts
 
       default:
-        throw new Error('MetamaskController - Unknown device')
+        throw new Error('MetamaskController:connectHardware - Unknown device')
     }
   }
 
+  /**
+   * Check if the device is unlocked
+   *
+   * @returns {Promise<boolean>}
+   */
   async checkHardwareStatus (deviceName) {
 
     switch (deviceName) {
@@ -574,12 +579,19 @@ module.exports = class MetamaskController extends EventEmitter {
           'Trezor Hardware'
         )[0]
         if (!keyring) {
-          return false
+          throw new Error('MetamaskController:checkHardwareStatus - Trezor Hardware keyring not found')
         }
         return keyring.isUnlocked()
+      default:
+        throw new Error('MetamaskController:checkHardwareStatus - Unknown device')
     }
   }
 
+  /**
+   * Clear
+   *
+   * @returns {Promise<boolean>}
+   */
   async forgetDevice (deviceName) {
 
     switch (deviceName) {
@@ -589,10 +601,12 @@ module.exports = class MetamaskController extends EventEmitter {
           'Trezor Hardware'
         )[0]
         if (!keyring) {
-          return false
+          throw new Error('MetamaskController:forgetDevice - Trezor Hardware keyring not found')
         }
         keyring.forgetDevice()
         return true
+      default:
+        throw new Error('MetamaskController:forgetDevice - Unknown device')
     }
   }
 
diff --git a/test/unit/app/controllers/metamask-controller-test.js b/test/unit/app/controllers/metamask-controller-test.js
index 0dda4609b..bef126f1f 100644
--- a/test/unit/app/controllers/metamask-controller-test.js
+++ b/test/unit/app/controllers/metamask-controller-test.js
@@ -222,6 +222,76 @@ describe('MetaMaskController', function () {
     })
   })
 
+  describe('connectHardware', function () {
+
+    it('should throw if it receives an unknown device name', async function () {
+      try {
+        await metamaskController.connectHardware('Some random device name', 0)
+      } catch (e) {
+        assert.equal(e, 'Error: MetamaskController:connectHardware - Unknown device')
+      }
+    })
+
+    it('should add the Trezor Hardware keyring', async function () {
+      await metamaskController.connectHardware('trezor', 0).catch((e) => null)
+      const keyrings = await metamaskController.keyringController.getKeyringsByType(
+        'Trezor Hardware'
+      )
+      assert.equal(keyrings.length, 1)
+    })
+
+  })
+
+  describe('checkHardwareStatus', function () {
+    it('should throw if it receives an unknown device name', async function () {
+      try {
+        await metamaskController.checkHardwareStatus('Some random device name')
+      } catch (e) {
+        assert.equal(e, 'Error: MetamaskController:checkHardwareStatus - Unknown device')
+      }
+    })
+
+    it('should be locked by default', async function () {
+      await metamaskController.connectHardware('trezor', 0).catch((e) => null)
+      const status = await metamaskController.checkHardwareStatus('trezor')
+      assert.equal(status, false)
+    })
+  })
+
+  describe('forgetDevice', function () {
+    it('should throw if it receives an unknown device name', async function () {
+      try {
+        await metamaskController.forgetDevice('Some random device name')
+      } catch (e) {
+        assert.equal(e, 'Error: MetamaskController:forgetDevice - Unknown device')
+      }
+    })
+
+    it('should wipe all the keyring info', async function () {
+      await metamaskController.connectHardware('trezor', 0).catch((e) => null)
+      await metamaskController.forgetDevice('trezor')
+      const keyrings = await metamaskController.keyringController.getKeyringsByType(
+        'Trezor Hardware'
+      )
+
+      assert.deepEqual(keyrings[0].accounts, [])
+      assert.deepEqual(keyrings[0].page, 0)
+      assert.deepEqual(keyrings[0].isUnlocked(), false)
+    })
+  })
+
+  describe('unlockTrezorAccount', function () {
+    it('should set accountToUnlock in the keyring', async function () {
+      await metamaskController.connectHardware('trezor', 0).catch((e) => null)
+      const accountToUnlock = 10
+      await metamaskController.unlockTrezorAccount(accountToUnlock).catch((e) => null)
+      const keyrings = await metamaskController.keyringController.getKeyringsByType(
+        'Trezor Hardware'
+      )
+      assert.equal(keyrings[0].unlockedAccount, accountToUnlock)
+    })
+  })
+
   describe('#setCustomRpc', function () {
     const customRPC = 'https://custom.rpc/'
     let rpcTarget