Add test for newlines in translations

Fixes #12

tests/crowdin_no_translations_has_newline.rs

@@ -0,0 +1,35 @@
+use std::fs;
+
+use fml::crowdin;
+use fml::util::read_dir;
+
+const IGNORED: &[(&str, &str, &str, &str)] = &[
+    // Empty translation for unknown reason, Crowdin support doesn't help
+    ("Factorio Ultracube (grandseiken)", "de", "tips-and-tricks.ini", "cube-boiler"),
+];
+
+#[tokio::test]
+async fn main() {
+    fml::init_with_crowdin().await;
+
+    let translations_directory = crowdin::download_all_translations().await;
+    let mut has_newlines = false;
+    // `ru/Factorio Mod Example (dima74)/locale.ini`
+    for (language_path, language) in read_dir(translations_directory.path()) {
+        for (repository_path, crowdin_name) in read_dir(&language_path) {
+            for (file_path, file_name) in read_dir(&repository_path) {
+                let content = fs::read_to_string(&file_path).unwrap();
+                for line in content.lines() {
+                    if let Some(key) = line.strip_suffix('=') {
+                        if IGNORED.contains(&(crowdin_name.as_str(), language.as_str(), file_name.as_str(), key)) {
+                            continue;
+                        }
+                        has_newlines = true;
+                        eprintln!("[{}] {}/{}: incorrect translation for key {}", crowdin_name, language, file_name, key)
+                    }
+                }
+            }
+        }
+    }
+    assert!(!has_newlines);
+}