refactor: internal package

internal/fileio/fileio.go

@@ -0,0 +1,39 @@
+// Package fileio provides high-level file operations.
+package fileio
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+)
+
+// CopyFile copies all files matching the pattern
+// to the destination directory.
+func CopyFiles(pattern string, dstDir string) error {
+	matches, err := filepath.Glob(pattern)
+	if err != nil {
+		return err
+	}
+
+	for _, match := range matches {
+		src, err := os.Open(match)
+		if err != nil {
+			return err
+		}
+		defer src.Close()
+
+		dstFile := filepath.Join(dstDir, filepath.Base(match))
+		dst, err := os.Create(dstFile)
+		if err != nil {
+			return err
+		}
+		defer dst.Close()
+
+		_, err = io.Copy(dst, src)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

internal/fileio/fileio_test.go

@@ -0,0 +1,56 @@
+package fileio
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestCopyFiles(t *testing.T) {
+	// Create a temporary directory for testing
+	srcDir, err := os.MkdirTemp("", "src")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(srcDir)
+
+	// Create a source file
+	srcFile := filepath.Join(srcDir, "source.txt")
+	err = os.WriteFile(srcFile, []byte("test data"), 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Specify the destination directory
+	dstDir, err := os.MkdirTemp("", "dst")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dstDir)
+
+	// Call the CopyFiles function
+	pattern := filepath.Join(srcDir, "*.txt")
+	err = CopyFiles(pattern, dstDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify that the file was copied correctly
+	dstFile := filepath.Join(dstDir, "source.txt")
+	_, err = os.Stat(dstFile)
+	if err != nil {
+		t.Fatalf("file not copied: %s", err)
+	}
+
+	// Read the contents of the copied file
+	data, err := os.ReadFile(dstFile)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify the contents of the copied file
+	expected := []byte("test data")
+	if string(data) != string(expected) {
+		t.Errorf("unexpected file content: got %q, want %q", data, expected)
+	}
+}