golang testing pattern

compute.go

package calc

import (
	"go/token"
	"go/types"
)

func Compute(expr string) (string, error) {
	tv, err := types.Eval(token.NewFileSet(), types.NewPackage("main", "main"), token.NoPos, expr)
	if err != nil {
		return "", err
	}
	return tv.Value.String(), nil
}

compute.txt

1+1=2
1.0/2.0=0.5

compute_test.go

package calc

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
	"testing"
	"testing/quick"
)

func TestCompute_simple(t *testing.T) {
	s, err := Compute("1+1")
	if err != nil {
		t.Fatal(err)
	}
	if s != "2" {
		t.Errorf("Compute(1+1) = %s, want 2", s)
	}
}

func TestCompute_with_table(t *testing.T) {
	computeTests := []struct {
		in  string
		out string
	}{
		{"1+1", "2"},
		{"1.0/2.0", "0.5"},
	}

	for _, test := range computeTests {
		s, err := Compute(test.in)
		if err != nil {
			t.Fatal(err)
		}
		if s != test.out {
			t.Errorf("Compute(%s) = %s, want %s", test.in, s, test.out)
		}
	}
}

func TestCompute_with_quicktest(t *testing.T) {
	add := func(a, b int16) bool {
		s, err := Compute(fmt.Sprintf("%d+%d", a, b))
		if err != nil {
			t.Fatal(err)
		}
		expected := strconv.Itoa(int(a) + int(b))
		if s != expected {
			t.Logf("Compute(%d+%d) = %s, want %s", a, b, s, expected)
			return false
		}
		return true
	}
	if err := quick.Check(add, nil); err != nil {
		t.Fatal(err)
	}
}

func TestCompute_with_tRun(t *testing.T) {
	t.Run("add sub", func(t *testing.T) {
		testCompute(t, "1+1", "2")
		testCompute(t, "-2+1", "-1")
	})
	t.Run("div", func(t *testing.T) {
		testCompute(t, "1.0/2.0", "0.5")
		testCompute(t, "2.0/1.0", "2")
	})
}

func testCompute(t *testing.T, in, expected string) {
	t.Helper()
	s, err := Compute(in)
	if err != nil {
		t.Fatal(err)
	}
	if s != expected {
		t.Errorf("Compute(%s) = %s, want %s", in, s, expected)
	}
}

func TestCompute_with_file(t *testing.T) {
	f, err := os.Open("testdata/compute.txt")
	if err != nil {
		t.Fatal(err)
	}
	defer f.Close()

	r := bufio.NewReader(f)
	for {
		line, _, err := r.ReadLine()
		if err == io.EOF {
			break
		}
		test := strings.Split(string(line), "=")
		if len(test) != 2 {
			t.Fatal("invalid test data: %s", string(line))
		}

		testCompute(t, test[0], test[1])
	}
}

func SetupComputeTest(t *testing.T, fname string) (*bufio.Reader, func()) {
	f, err := os.Open(fname)
	if err != nil {
		t.Fatal(err)
	}
	return bufio.NewReader(f), func() {
		f.Close()
	}
}

func TestCompute_with_setupFunc(t *testing.T) {
	r, Teardown := SetupComputeTest(t, "testdata/compute.txt")
	defer Teardown()

	for {
		line, _, err := r.ReadLine()
		if err == io.EOF {
			break
		}
		test := strings.Split(string(line), "=")
		if len(test) != 2 {
			t.Fatal("invalid test data: %s", string(line))
		}

		testCompute(t, test[0], test[1])
	}
}

type computeTest struct {
	testing.TB
	f *os.File
	r *bufio.Reader
}

func SetupComputeTest2(tb testing.TB, fname string) *computeTest {
	f, err := os.Open(fname)
	if err != nil {
		tb.Fatal(err)
	}

	return &computeTest{
		TB: tb,
		f:  f,
		r:  bufio.NewReader(f),
	}
}

func (t *computeTest) Teardown() {
	t.f.Close()
}

func (t *computeTest) testData() (in, out string, ok bool) {
	line, _, err := t.r.ReadLine()
	if err == io.EOF {
		return "", "", false
	}
	test := strings.Split(string(line), "=")
	if len(test) != 2 {
		t.Fatal("invalid test data: %s", string(line))
	}
	return test[0], test[1], true
}

func TestCompute_with_testutil(tt *testing.T) {
	t := SetupComputeTest2(tt, "testdata/compute.txt")
	defer t.Teardown()

	for {
		in, out, ok := t.testData()
		if !ok {
			break
		}
		testCompute(tt, in, out)
	}
}

https://qiita.com/atotto/items/f6b8c773264a3183a53c

go test -v
=== RUN   TestCompute_simple
--- PASS: TestCompute_simple (0.00s)
=== RUN   TestCompute_with_table
--- PASS: TestCompute_with_table (0.00s)
=== RUN   TestCompute_with_quicktest
--- PASS: TestCompute_with_quicktest (0.00s)
=== RUN   TestCompute_with_tRun
=== RUN   TestCompute_with_tRun/add_sub
=== RUN   TestCompute_with_tRun/div
--- PASS: TestCompute_with_tRun (0.00s)
    --- PASS: TestCompute_with_tRun/add_sub (0.00s)
    --- PASS: TestCompute_with_tRun/div (0.00s)
=== RUN   TestCompute_with_file
--- PASS: TestCompute_with_file (0.00s)
=== RUN   TestCompute_with_setupFunc
--- PASS: TestCompute_with_setupFunc (0.00s)
=== RUN   TestCompute_with_testutil
--- PASS: TestCompute_with_testutil (0.00s)
PASS