Functions API build tests (#8344)

* Functions API build tests

* Fix copyright

Author: ncooke3

FirebaseFunctions.podspec

@@ -43,6 +43,7 @@ Cloud Functions for Firebase.
     unit_tests.scheme = { :code_coverage => true }
     unit_tests.source_files = [
       'Functions/Example/Test*/*.[mh]',
+      'Functions/Tests/Unit/Swift/**/*',
       'SharedTestUtilities/FIRAuthInteropFake*',
       'SharedTestUtilities/FIRMessagingInteropFake*',
       'SharedTestUtilities/AppCheckFake/*.[mh]',

Functions/Tests/Unit/Swift/FunctionsAPITests.swift

@@ -0,0 +1,144 @@
+//
+// Copyright 2021 Google LLC
+//
+// 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.
+//
+
+// MARK: This file is used to evaluate the experience of using Firebase APIs in Swift.
+
+import Foundation
+
+import FirebaseCore
+import FirebaseFunctions
+
+final class FunctionsAPITests {
+  func usage() {
+    // MARK: - Functions
+
+    // Retrieve Functions instance
+    _ = Functions.functions()
+
+    if let app = FirebaseApp.app() {
+      _ = Functions.functions(app: app)
+      _ = Functions.functions(app: app, region: "alderaan")
+      _ = Functions.functions(app: app, customDomain: "https://visitalderaan.com")
+    }
+
+    _ = Functions.functions(region: "alderaan")
+    _ = Functions.functions(customDomain: "https://visitalderaan.com")
+
+    // Reference to a callable HTTPS trigger
+    _ = Functions.functions().httpsCallable("setCourseForAlderaan")
+
+    // Functions emulator
+    Functions.functions().useEmulator(withHost: "host", port: 3000)
+    if let _ /* emulatorOrigin */ = Functions.functions().emulatorOrigin {
+      // ...
+    }
+
+    // MARK: - HTTPSCallable
+
+    let callableRef = Functions.functions().httpsCallable("setCourseForAlderaan")
+    callableRef.timeoutInterval = 60
+
+    let data: Any? = nil
+    callableRef.call(data) { result, error in
+      if let result = result {
+        _ = result.data
+      } else if let _ /* error */ = error {
+        // ...
+      }
+    }
+
+    #if swift(>=5.5)
+      if #available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, *) {
+        // async/await is a Swift 5.5+ feature available on iOS 15+
+        async {
+          do {
+            let result = try await callableRef.call(data)
+            _ = result.data
+          } catch {
+            // ...
+          }
+        }
+      }
+    #endif // swift(>=5.5)
+
+    callableRef.call { result, error in
+      if let result = result {
+        _ = result.data
+      } else if let _ /* error */ = error {
+        // ...
+      }
+    }
+
+    #if swift(>=5.5)
+      if #available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, *) {
+        // async/await is a Swift 5.5+ feature available on iOS 15+
+        async {
+          do {
+            let result = try await callableRef.call()
+            _ = result.data
+          } catch {
+            // ...
+          }
+        }
+      }
+    #endif // swift(>=5.5)
+
+    // MARK: - FunctionsErrorCode
+
+    callableRef.call { _, error in
+      if let error = error {
+        switch (error as NSError).code {
+        case FunctionsErrorCode.OK.rawValue:
+          break
+        case FunctionsErrorCode.cancelled.rawValue:
+          break
+        case FunctionsErrorCode.unknown.rawValue:
+          break
+        case FunctionsErrorCode.invalidArgument.rawValue:
+          break
+        case FunctionsErrorCode.deadlineExceeded.rawValue:
+          break
+        case FunctionsErrorCode.notFound.rawValue:
+          break
+        case FunctionsErrorCode.alreadyExists.rawValue:
+          break
+        case FunctionsErrorCode.permissionDenied.rawValue:
+          break
+        case FunctionsErrorCode.resourceExhausted.rawValue:
+          break
+        case FunctionsErrorCode.failedPrecondition.rawValue:
+          break
+        case FunctionsErrorCode.aborted.rawValue:
+          break
+        case FunctionsErrorCode.outOfRange.rawValue:
+          break
+        case FunctionsErrorCode.unimplemented.rawValue:
+          break
+        case FunctionsErrorCode.internal.rawValue:
+          break
+        case FunctionsErrorCode.unavailable.rawValue:
+          break
+        case FunctionsErrorCode.dataLoss.rawValue:
+          break
+        case FunctionsErrorCode.unauthenticated.rawValue:
+          break
+        default:
+          break
+        }
+      }
+    }
+  }
+}