How to write unit tests for encoding and decoding functions in Go?

To write unit tests for encoding and decoding functions in Go, you can follow these steps:

Create a new test file: Create a new file with the name example_test.go. This naming convention is important as Go's testing package recognizes files that end with _test.go as test files.
Import the necessary packages: Import the packages required for testing. You will need the testing package for writing tests and the package that contains your encoding and decoding functions.

package main

import (
	"testing"
	"your-package-name" // Import the package containing the encoding and decoding functions
)

Write the test function: Write a test function with a name starting with Test followed by a descriptive name. The test function should accept a *testing.T parameter, which is used for reporting test failures or successes.

func TestEncode(t *testing.T) {
	// Write your test code here
}

Write the test cases: Inside the test function, write test cases for the encoding function. Each test case should involve providing inputs to the encoding function and checking if the output matches the expected result. Use the t.Run() function to separate different test cases.

func TestEncode(t *testing.T) {
	cases := []struct {
		input    string
		expected string
	}{
		{input: "hello", expected: "encoded-hello"},
		{input: "world", expected: "encoded-world"},
		{input: "go", expected: "encoded-go"},
	}

	for _, tc := range cases {
		t.Run(tc.input, func(t *testing.T) {
			output := yourpackage.Encode(tc.input)
			if output != tc.expected {
				t.Errorf("Encode(%q) = %q, expected %q", tc.input, output, tc.expected)
			}
		})
	}
}

Repeat the same steps for the decoding function: Repeat steps 3 and 4 for the decoding function. Write a new test function starting with TestDecode and define the test cases.

func TestDecode(t *testing.T) {
	cases := []struct {
		input    string
		expected string
	}{
		{input: "encoded-hello", expected: "hello"},
		{input: "encoded-world", expected: "world"},
		{input: "encoded-go", expected: "go"},
	}

	for _, tc := range cases {
		t.Run(tc.input, func(t *testing.T) {
			output := yourpackage.Decode(tc.input)
			if output != tc.expected {
				t.Errorf("Decode(%q) = %q, expected %q", tc.input, output, tc.expected)
			}
		})
	}
}

Run the tests: To run the tests, navigate to the package directory in the terminal and execute the command go test. Go will automatically discover and run the test functions.

$ go test

That's it! You have written unit tests for the encoding and decoding functions in Go. Running go test will execute the test functions and report any failures or successes.