refactor: extract read all text method to file package

internal/file/file.go

@@ -24,3 +24,13 @@ func ReadLines(filePath string) []string {
 
 	return lines
 }
+
+func ReadAllText(filePath string) string {
+	fileContent, readErr := os.ReadFile(filePath)
+
+	if readErr != nil {
+		return ""
+	}
+
+	return string(fileContent)
+}

internal/file/file_test.go

@@ -19,3 +19,13 @@ func TestReadLines(t *testing.T) {
 		t.Errorf("got %s but expected %s", result, expectedLines)
 	}
 }
+
+func TestReadAllText(t *testing.T) {
+	expectedText := "hello\r\nworld\r\n"
+
+	result := file.ReadAllText("test.txt")
+
+	if result != expectedText {
+		t.Errorf("got %q but expected %q", result, expectedText)
+	}
+}