How to measure test coverage in Go
Overview
Go comes with a convenient tool for testing and coverage. Let’s create the following code for this shot. We have also added a test file below.
Example
We can execute the go test command from the folder containing the two files.
package main
import "testing"
func TestAdd(t *testing.T) {
if got, want := World(1), "New World!"; got != want {
t.Errorf("World method produced wrong result. expected: %s, got: %s", want, got)
}
}
When Go test is run, it executes the tests and prints either “PASS” or “FAIL”. Go allows us to get the coverage report with the built-in options to test command.
package main
import "testing"
func TestAdd(t *testing.T) {
if got, want := World(1), "New World!"; got != want {
t.Errorf("World method produced wrong result. expected: %s, got: %s", want, got)
}
}
We can also get a coverage report with line by line coverage details as follows:
package main
import "testing"
func TestAdd(t *testing.T) {
if got, want := World(1), "New World!"; got != want {
t.Errorf("World method produced wrong result. expected: %s, got: %s", want, got)
}
}
After executing Executing "go tool cover -html=coverage.out -o coverage.html command we get coverage.html file in our current directory. The following image shows the result of the HTML file.
As seen in the image above, the coverprofile gives us the details of the lines that have been covered by the tests versus those that have not been covered.
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Anjana Shankar