test: Initial unit testing

- Test quests vector loading
- Test default quest on empty fields
- Test correct quest
- Fixed config paths handling

tests/main.rs

@@ -0,0 +1,40 @@
+use squad_quest::{config::Config, quest::Quest};
+
+#[test]
+fn load_quests() {
+    let config = Config::load("./tests/cfg/config.toml".into());
+    let quests = config.load_quests();
+
+    assert_eq!(quests.len(), 2);
+}
+
+#[test]
+fn empty_quest_is_default() {
+    // First loaded quest should be 0.toml, which is empty
+    let config = Config::load("./tests/cfg/config.toml".into());
+    let mut quests = config.load_quests();
+    quests.sort_by(|a,b| a.id.cmp(&b.id));
+    let quest = quests.first().unwrap();
+    
+    let default = Quest::default();
+
+    assert_eq!(*quest, default);
+}
+
+#[test]
+fn quest_one() {
+    let config = Config::load("./tests/cfg/config.toml".into());
+    let quests = config.load_quests();
+    let quest = quests.iter().find(|q| q.id == 1).unwrap();
+    
+    let expected = Quest {
+        id: 1,
+        difficulty: squad_quest::quest::QuestDifficulty::Easy,
+        reward: 100,
+        name: "Example easy quest".to_owned(),
+        description: "Answer this quest without any attachments or comments".to_owned(),
+        answer: "Accept the answer if it has no attachments and an empty comment".to_owned()
+    };
+
+    assert_eq!(*quest, expected);
+}