Going from a passing test to a failing test is a regression

-- p_test.go --
package p

import "testing"

func TestP(t *testing.T) {
}

-- .commit --
Initial commit with passing test

-- p_test.go --
package p

import "testing"

func TestP(t *testing.T) {
	t.FailNow()
}

-- .commit --
Break test

-- .run_test --
Test regressions detected between initial commit (149798f10aaf06bc4700bb62d46ed6d8d88e35ad) and HEAD:

1: sketch.dev.TestP: Was passing, now failing


Please fix before proceeding.