[short] skip
go test -cover ./pkg1 ./pkg2 ./pkg3 ./pkg4
stdout 'pkg1	\[no test files\]'
stdout 'pkg2	\S+	coverage: 0.0% of statements \[no tests to run\]'
stdout 'pkg3	\S+	coverage: 100.0% of statements'
stdout 'pkg4	\S+	coverage: \[no statements\]'

-- go.mod --
module m

go 1.16
-- pkg1/a.go --
package pkg1

import "fmt"

func F() {
	fmt.Println("pkg1")
}
-- pkg2/a.go --
package pkg2

import "fmt"

func F() {
	fmt.Println("pkg2")
}
-- pkg2/a_test.go --
package pkg2
-- pkg3/a.go --
package pkg3

import "fmt"

func F() {
	fmt.Println("pkg3")
}
-- pkg3/a_test.go --
package pkg3

import "testing"

func TestF(t *testing.T) {
	F()
}
-- pkg4/a.go --
package pkg4

type T struct {
	X bool
}
-- pkg4/a_test.go --
package pkg4

import (
	"testing"
)

func TestT(t *testing.T) {
	_ = T{}
}