Powerful Command-Line Applications in Go/

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Writing Tests for colStats

Writing Tests for colStats

Get an introduction to the test cases for the colStats tool .

We'll cover the following...

We’re going to make a lot of changes to this code base to improve its performance. Before doing that, let’s write tests to make sure the program works correctly. Then we can use those tests to ensure the program still works as we change the underlying code.

We’ll create unit tests for the avg() and sum() statistics functions, as well as for the csv2float() function. For the integration tests, we’ll test the function run(). We’ll also apply table-driven testing.

Creating the csv_test.go file

Let’s start by writing unit tests for the statistics operations. In the same directory as the csv.go file, we create the tests file csv_test.go. We open it in our text editor and add the package section:

package main
Adding the package

For these tests, we’ll use:

  • The bytes package to create buffers to capture the output.
  • The errors package to validate errors.
  • The io package to use the io.Reader interface.
  • The testing package, which is required to execute tests.
  • The iotest package to assist in executing tests that fail to read data.
import (
  "bytes"
  "errors"
  "fmt"
  "io"
  "testing"
  "testing/iotest"
)
The import section

Defining the TestOperations() function

Add the definition for the first test function TestOperations(). We’ll use a single test function to test all operation functions by ...