How Can I Guarantee Sequential Test Execution in Go?

Sequential Execution in Go Tests

When running Go tests, it's plausible to encounter inconsistencies in test results, as witnessed by the initial failures followed by successful runs. This inconsistency typically arises in situations where tests rely on prior actions, such as creating database records before performing retrieval operations.

The Problem of Test Order

Go's testing framework doesn't guarantee the execution order of tests. This can lead to issues when tests depend on the results of previous tests. For instance, if a GET request relies on a POST request to create data, the GET request might fail if the POST request hasn't been executed yet.

Solutions for Sequential Execution

Since test execution order is unreliable, it's crucial to ensure that tests are independent of each other. However, if this is not feasible, there are several options to execute specific tasks before running a test function:

• Test Function Initialization: Include the necessary setup code within the test function itself.
• Package Initialization (init() Function): Place the setup code in the _test.go file's init() function, which executes once before any test functions.
• TestMain() Function: Implement a TestMain() function, which is invoked first and allows for additional setup before calling M.Run() to trigger test function execution.
• Mixing Options: Combine any of these approaches to achieve the desired sequence.

Solving the Database Setup Issue

In the specific case presented, you should add the necessary setup code to the init() or TestMain() function to check if your database has been initialized and, if not, insert the test records.

Note on Subtests

Starting with Go 1.7, subtests provide a means to control test execution order. Subtests are nested within a test function and can be used to define specific dependencies and execution sequences. Refer to the Go testing documentation for more details.

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