PCD Building and testing applications Practice Test 5 — 15 Questions

Question 1

A developer is writing unit tests for a Cloud Function that interacts with Cloud Storage. They want to avoid making real API calls during tests to ensure fast and reliable execution. Which two practices should they follow? (Choose two.)

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Use the Google Cloud Storage emulator to simulate Cloud Storage locally and configure the client library to connect to it.. To avoid real API calls in unit tests for Cloud Storage, developers can either use the Cloud Storage emulator for a local simulation or mock the client library to return controlled responses. Both approaches eliminate network dependencies and make tests fast and reliable.

Answer

Create a test bucket in Cloud Storage and use it for all tests, cleaning up objects after each test run.

Answer

Set the STORAGE_EMULATOR_HOST environment variable to point to a local emulator instance.

Answer

Use the gcloud storage command-line tool to interact with Cloud Storage in tests.

Question 2

A developer is deploying a new Cloud Run service using the gcloud CLI. They want to ensure the service is production-ready and follows Google-recommended practices for building and testing. Which two actions should they take? (Choose two.)

Accepted Answer

Configure a minimum number of instances to avoid cold starts and ensure availability.. Enabling CPU boost reduces cold start latency, and setting a minimum instance count keeps instances warm to avoid cold starts. Both are recommended for production Cloud Run services that require consistent performance. They address startup latency and availability, which are key concerns for user-facing services.

Answer

Deploy the service with the --no-traffic flag to validate the new revision before sending traffic.

Answer

Set the --max-instances flag to a high value to handle unlimited traffic spikes.

Answer

Use the --allow-unauthenticated flag to simplify access for all users.

Question 3

A developer is building a Cloud Run service that connects to Cloud SQL for PostgreSQL. The service uses the Cloud SQL Python Connector. During local testing with the Cloud SQL Auth Proxy, the connection succeeds. After deployment to Cloud Run, the service fails to connect with a permission denied error. The service account has the Cloud SQL Client role. What is the most likely cause?

Accepted Answer

The Cloud SQL Auth Proxy is not running in the Cloud Run container, and the service is trying to connect to localhost instead of using the Cloud SQL Python Connector.. The Cloud SQL Python Connector is designed for serverless environments like Cloud Run and does not require the Auth Proxy. If the application is configured to use the proxy's localhost endpoint, it will fail in Cloud Run. The connector uses the service account's IAM permissions and the Cloud SQL Admin API. Ensuring the code uses the connector directly resolves the issue.

Answer

The Cloud SQL Python Connector requires the Cloud SQL Admin API to be enabled and the service account to have the cloudsql.instances.connect permission, which the Cloud SQL Client role includes, but the connector may be using the wrong credentials.

Answer

The Cloud Run service account lacks the Cloud SQL Client role on the specific instance, or the instance connection name is incorrect.

Answer

The Cloud SQL instance does not have a public IP address, and Cloud Run requires a Serverless VPC Access connector to reach it.

Question 4

A developer is using Cloud Build to run unit tests for a Node.js application. The tests require a temporary directory to store test artifacts. Which Cloud Build configuration ensures the temporary directory is available during the build steps?

Accepted Answer

Include a build step that runs `mkdir -p /tmp/test-artifacts` before the test step.. In Cloud Build, each build step runs in a container with a writable filesystem. To ensure a temporary directory is available during the build, the most straightforward method is to create it within the build step using a command like `mkdir -p /tmp/test-artifacts`. This guarantees the directory exists for that step. If multiple steps need to share the directory, a volume can be used, but the question does not specify multi-step sharing.

Answer

Use the `dir` field in the build step to set the working directory to `/tmp`.

Answer

Add a `volumes` section with a volume named `temp` and mount it to `/tmp` in the test step.

Answer

Add a `volumes` section in the build step to mount a temporary directory from the host.

Question 5

A developer is using Cloud Build to run unit tests for a Python application. The tests require a specific version of a Python package that is not available in the default Cloud Build environment. The developer wants to ensure that the build fails if the tests fail. What should the developer do?

Accepted Answer

Add a build step that uses a custom builder image with the required package pre-installed and runs the tests.. A custom builder image is the most reliable way to ensure the required package version and dependencies are available. It encapsulates the environment and can be reused across builds. Running tests in that step will cause the build to fail if tests fail, meeting the requirement. Other methods either do not guarantee the correct environment or add unnecessary complexity.

Answer

Configure the build to use a private pool that has the package pre-installed.

Answer

Store the package in a Cloud Storage bucket and add a build step to download and install it.

Answer

Use the default Python builder image and install the package at the beginning of the build using pip.

Question 6

A developer is writing a Cloud Function in Python that uses the requests library to call an external API. They want to test the function locally using the Functions Framework. Which command should they run to start the local server?

Accepted Answer

functions-framework --target=my_function --signature-type=http. The Functions Framework is the official tool for running Cloud Functions locally. The command functions-framework --target=my_function --signature-type=http starts a local HTTP server that invokes the specified function. This allows the developer to test the function's behavior without deploying to Google Cloud, ensuring fast iteration and debugging.

Answer

python -m functions_framework --target=my_function

Answer

docker run --rm -p 8080:8080 gcr.io/cloud-functions/my_function

Answer

gcloud functions deploy my_function --runtime=python39 --trigger-http

Question 7

A developer is writing a Cloud Build configuration to run unit tests for a Node.js application. The tests require a specific version of Node.js and need to install dependencies from a private npm registry. The build should fail if any test fails. What should the developer include in the cloudbuild.yaml?

Accepted Answer

Use the gcr.io/cloud-builders/npm builder with the script 'test' and set the NPM_TOKEN substitution for the private registry.. The gcr.io/cloud-builders/npm builder is the standard way to run npm commands in Cloud Build. Running the 'test' script executes the project's tests, and a non-zero exit fails the build. Private registry authentication can be provided via substitutions or Secret Manager. Other options either use incorrect builders or insecure practices.

Answer

Use a custom builder that runs 'npm test' and hardcode the private registry credentials in the cloudbuild.yaml.

Answer

Use the gcr.io/cloud-builders/npm builder with the 'install' command followed by 'test', and use Cloud Key Management Service to encrypt the npm token.

Answer

Use the gcr.io/cloud-builders/nodejs builder with the 'test' argument and store the private registry token in a Cloud Storage bucket.

Question 8

A team is building a Cloud Run service that uses a custom container. They want to run the container locally for testing before deployment. The container listens on port 8080. Which command correctly runs the container locally with the Cloud Run emulator, ensuring it behaves like the deployed service?

Accepted Answer

`gcloud beta code dev --local-port=8080 --image=gcr.io/my-project/my-service`. The `gcloud beta code dev` command is designed for local development of Cloud Run services. It runs the container locally and emulates the Cloud Run environment, including setting the `PORT` environment variable to the specified local port. This ensures the container behaves similarly to when it is deployed. Using plain `docker run` does not replicate Cloud Run's environment, and other commands are not valid for local emulation.

Answer

`gcloud run deploy --local --port=8080 --image=gcr.io/my-project/my-service`

Answer

`docker run -p 8080:8080 gcr.io/my-project/my-service`

Answer

`gcloud run local run --port=8080 --image=gcr.io/my-project/my-service`

Question 9

A developer is building a Node.js service on Cloud Run that receives events from Pub/Sub. They want to test the service locally to verify that it correctly parses the Pub/Sub message payload. Which approach should they use?

Accepted Answer

Use the Functions Framework to run the service locally and send a test request with a simulated Pub/Sub message payload.. The Functions Framework is designed for local development of event-driven services. It emulates the runtime environment and allows invoking functions with Pub/Sub message payloads, ensuring that the service's parsing logic is tested against the correct format. Other options either rely on non-existent tools or incorrectly mix local and cloud components, failing to provide a valid local testing approach.

Answer

Write a unit test that directly calls the service's HTTP endpoint with a crafted JSON payload that mimics a Pub/Sub message.

Answer

Run the service locally with the Cloud Run emulator and send a Pub/Sub message using the Pub/Sub emulator.

Answer

Deploy the service to Cloud Run and use the Pub/Sub emulator to publish messages to the deployed service.

Question 10

A team is developing a Python web application that will be deployed to App Engine standard environment. They want to run the application locally with the same runtime and services as production. Which two actions should they take to achieve this? (Choose two.)

Accepted Answer

Use the Cloud SDK's dev_appserver.py tool to run the application locally with the App Engine runtime.. To run a Python application locally with the same runtime and services as App Engine standard, developers should use the local development server provided by the Cloud SDK, typically via dev_appserver.py. This tool emulates the runtime and bundled services, enabling realistic local testing. Other actions like setting environment variables or using Compute Engine do not replicate the App Engine standard environment and are not part of the recommended local development workflow.

Answer

Set the environment variable GAE_ENV to 'standard' in the local development environment.

Answer

Configure the local environment to use the Cloud SQL Auth Proxy for any Cloud SQL connections.

Answer

Deploy the application to a Compute Engine instance and use it as a local test environment.

Question 11

A developer is building a Cloud Function in Node.js that publishes a message to Pub/Sub. During local testing with the Functions Framework, the function fails with an authentication error when trying to publish. The developer is authenticated with gcloud and has the Pub/Sub Publisher role. What should the developer do to allow the local function to publish messages?

Accepted Answer

Set the GOOGLE_APPLICATION_CREDENTIALS environment variable to point to a service account key file with the Pub/Sub Publisher role.. Local testing of Cloud Functions with the Functions Framework often requires explicit credentials for Google Cloud APIs. While gcloud auth application-default login can work, using a service account key file via GOOGLE_APPLICATION_CREDENTIALS is more reliable and mirrors production permissions. The --service-account flag is not available locally, and enabling APIs or changing roles does not resolve authentication errors.

Answer

Use the gcloud auth application-default login command to obtain ADC for the user, which will automatically grant the Pub/Sub Publisher role.

Answer

Run the function with the --service-account flag to specify the service account email.

Answer

Enable the Pub/Sub API and ensure the gcloud user has the Pub/Sub Admin role.

Question 12

A developer is building a Go service that will run on Cloud Run. The service must read a secret from Secret Manager at startup. During local testing, the developer wants to avoid embedding credentials and wants the same code to work in production without changes. Which approach should the developer use?

Accepted Answer

Use the Secret Manager client library with Application Default Credentials, and grant the Cloud Run service account the Secret Manager Secret Accessor role.. The correct approach is to use the Secret Manager client library with Application Default Credentials (ADC). ADC automatically discovers credentials from the local development environment (via gcloud auth application-default login) or from the service account attached to the Cloud Run service. Granting the Secret Manager Secret Accessor role to the Cloud Run service account ensures least-privilege access in production. This method keeps code consistent across environments.

Answer

Mount the secret as a volume in Cloud Run and read it from the filesystem, using a local file during development.

Answer

Hardcode the secret in an environment variable and pass it to Cloud Run via the --set-env-vars flag, while using a .env file locally.

Answer

Store the secret in a Cloud Storage bucket and download it at startup using a public URL.

Question 13

A developer is building a Python service on Cloud Run that writes to Cloud Storage. The service uses the google-cloud-storage library. During local testing, the developer wants to verify that the code correctly handles a bucket that does not exist. Which action should the developer take to simulate this error without making real API calls?

Accepted Answer

Use the unittest.mock library to patch the storage.Client method that retrieves the bucket and raise a google.api_core.exceptions.NotFound exception.. Mocking the storage client method to raise a NotFound exception is the most direct and reliable way to test error handling for a missing bucket. It avoids network calls, credentials, and external dependencies, and it precisely simulates the exception that the application would encounter in production. This allows the developer to verify that the code correctly catches and handles the error, such as by logging a message or returning a fallback response.

Answer

Use the google-cloud-storage client's built-in mock mode by setting the GOOGLE_CLOUD_STORAGE_MOCK environment variable to true.

Answer

Create a test bucket in Cloud Storage with a name that is unlikely to exist, and configure the application to use that bucket name.

Answer

Set the STORAGE_EMULATOR_HOST environment variable to point to a local emulator and configure the emulator to return a 404 for the bucket.

Question 14

A developer is building a Cloud Run service that reads messages from a Pub/Sub subscription. They want to write integration tests that run in a CI/CD pipeline without connecting to production Google Cloud services. Which two actions should they take? (Choose two.)

Accepted Answer

Start the Pub/Sub emulator in the CI/CD pipeline and set the PUBSUB_EMULATOR_HOST environment variable to its address.. To run integration tests in CI/CD without production services, start the Pub/Sub emulator and configure the application to connect to it via the PUBSUB_EMULATOR_HOST environment variable. Additionally, run the Cloud Run service locally (e.g., in a Docker container) so that it can interact with the emulator. This setup provides a self-contained test environment that mimics Pub/Sub interactions without external dependencies.

Answer

Use the gcloud pubsub emulator start command to launch the emulator and then create the necessary topics and subscriptions using gcloud pubsub commands.

Answer

Use the Cloud Pub/Sub client library's mock mode by setting the PUBSUB_EMULATOR_HOST environment variable to a special value like 'mock'.

Answer

Configure the application to use a test project ID and service account with limited permissions to isolate test resources from production.

Question 15

A developer is writing unit tests for a Cloud Function that interacts with Cloud Storage. They want to avoid making real API calls during tests to ensure fast and reliable execution. Which two practices should they follow? (Choose two.)

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Mock the @google-cloud/storage client library in the unit tests to return predefined responses.. For unit testing a Node.js Cloud Function that uses Cloud Storage, mocking the @google-cloud/storage library is the most effective approach. It isolates the function's logic, eliminates network dependencies, and allows precise control over return values and errors. This is standard practice and aligns with the goal of running tests locally without accessing the real API.

Answer

Use the Cloud Storage emulator provided by the Google Cloud SDK to simulate the API locally.

Answer

Configure the function to use a test bucket with a service account that has limited permissions.

Answer

Set the STORAGE_EMULATOR_HOST environment variable to point to a local mock server.