Tests for grep_parallel.go file (https://gist.github.com/chinmay185/0a188fffba38d4436836b567bb0b7ac8)

grep_parallel_test.go

package grep

import (
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"
)

type testProcessor struct {
	files []string
}

func (t *testProcessor) Process(name string) {
	t.files = append(t.files, name)
}

func TestWalker(t *testing.T) {
	t.Run("test walk", func(t *testing.T) {
		parent, err := setupDirs()
		defer removeDirs(parent)
		if err != nil {
			t.Errorf("cannot complete setup %+v", err)
			return
		}

		dummy := &testProcessor{}
		w := makeWalker(".go", parent)

		// when
		w.Walk(dummy)

		// then
		if len(dummy.files) != 2 {
			t.Errorf("expected 2 found %d\n", len(dummy.files))
		}
	})
}

func TestGrepper(t *testing.T) {
	t.Run("test Process", func(t *testing.T) {
		path, err := setupFile()
		defer removeFile(path)
		if err != nil {
			t.Errorf("cannot complete setup %+v", err)
			return
		}

		var wg sync.WaitGroup
		results := make(chan []string)
		g := makeGrepper(results, &wg, "test")

		// when
		g.Process(path)

		// then
		t.Run("test results", func(t *testing.T) {
			select {
			case res := <-results:
				if len(res) != 0 {
					t.Errorf("results should have been empty but got %+v", res)
				}
			case <-time.After(1 * time.Second):
				t.Error("timeout, couldn't read from results channel in 1 second")
			}
		})
		t.Run("test waitgroup", func(t *testing.T) {
			done := make(chan bool)
			go func(d chan bool) {
				wg.Wait()
				d <- true
			}(done)
			select {
			case <-done:
			case <-time.After(1 * time.Second):
				t.Error("timeout, wait group didn't complete in 1 second")
			}
		})
	})

	t.Run("test search", func(t *testing.T) {
		var wg sync.WaitGroup
		g := makeGrepper(make(chan []string), &wg, "test")
		matchingLine1 := "line1 test"
		matchingLine2 := "testline2"
		nonMatchingLine := "something else"
		reader := strings.NewReader(strings.Join([]string{matchingLine1, nonMatchingLine, matchingLine2}, "\n"))
		prefix := "/prefix"

		// when
		results := g.search(reader, prefix)

		// then
		expectedResults := []string{prefix + ":" + matchingLine1, prefix + ":" + matchingLine2}
		if len(expectedResults) != len(results) {
			t.Errorf("expected length %d but found %d", len(expectedResults), len(results))
			return
		}
		for i := range expectedResults {
			if expectedResults[i] != results[i] {
				t.Errorf("expected %s but got %s", expectedResults[i], results[i])
			}
		}
	})
}

func setupFile() (string, error) {
	path := filepath.Join(".", "__test_file__.go")
	if _, err := os.Create(path); err != nil {
		return "", err
	}
	return path, nil
}
func removeFile(path string) {
	os.Remove(path)
}

func setupDirs() (string, error) {
	parent := filepath.Join(".", "__test__")
	dir1 := filepath.Join(parent, "dir1")
	dir2 := filepath.Join(dir1, "dir2")

	os.MkdirAll(dir2, 0755)

	if _, err := os.Create(filepath.Join(dir1, "file1.go")); err != nil {
		return "", err
	}
	if _, err := os.Create(filepath.Join(dir2, "file2.go")); err != nil {
		return "", err
	}
	return parent, nil
}
func removeDirs(parent string) {
	os.RemoveAll(parent)
}