Add UI tests for optional app lock setup. (#2046)

ElementX/Sources/Services/AppLock/LAContextMock.swift

@@ -0,0 +1,48 @@
+//
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import LocalAuthentication
+
+/// A customised context that allows injecting a few mock values but otherwise behaves as expected.
+/// It works as the actual context does and won't update the return values of `biometryType` and
+/// `evaluatedPolicyDomainStateValue` until either `canEvaluatePolicy` or
+/// `evaluatePolicy` have been called.
+class LAContextMock: LAContext {
+    var biometryTypeValue: LABiometryType!
+    private var internalBiometryTypeValue: LABiometryType!
+    override var biometryType: LABiometryType { internalBiometryTypeValue }
+    
+    var evaluatedPolicyDomainStateValue: Data?
+    private var internalEvaluatedPolicyDomainStateValue: Data?
+    override var evaluatedPolicyDomainState: Data? { internalEvaluatedPolicyDomainStateValue }
+    
+    override func canEvaluatePolicy(_ policy: LAPolicy, error: NSErrorPointer) -> Bool {
+        let result = super.canEvaluatePolicy(policy, error: error)
+        updateInternalValues()
+        return result
+    }
+    
+    var evaluatePolicyReturnValue: Bool!
+    override func evaluatePolicy(_ policy: LAPolicy, localizedReason: String) async throws -> Bool {
+        updateInternalValues()
+        return evaluatePolicyReturnValue
+    }
+    
+    private func updateInternalValues() {
+        internalBiometryTypeValue = biometryTypeValue
+        internalEvaluatedPolicyDomainStateValue = evaluatedPolicyDomainStateValue
+    }
+}