frontend: Make features code more modular

By making it more modular it is easier to add
unit tests fro current behavior.

src/web/features.rs

@@ -9,6 +9,8 @@ use router::Router;
 use serde::Serialize;
 use std::collections::{HashMap, VecDeque};
 
+const DEFAULT_NAME: &str = "default";
+
 #[derive(Debug, Clone, PartialEq, Eq, Serialize)]
 struct FeaturesPage {
     metadata: MetaData,
@@ -38,28 +40,14 @@ pub fn build_features_handler(req: &mut Request) -> IronResult<Response> {
 
     let row = cexpect!(req, rows.get(0));
 
+    let mut features = None;
     let mut default_len = 0;
-    let features = row
-        .get::<'_, usize, Option<Vec<Feature>>>(0)
-        .map(|raw| {
-            raw.into_iter()
-                .filter(|feature| !feature.is_private())
-                .map(|feature| (feature.name.clone(), feature))
-                .collect::<HashMap<String, Feature>>()
-        })
-        .map(|mut feature_map| {
-            let mut features = get_tree_structure_from_default(&mut feature_map);
-            let mut remaining = feature_map
-                .into_iter()
-                .map(|(_, feature)| feature)
-                .collect::<Vec<Feature>>();
-            remaining.sort_by_key(|feature| feature.subfeatures.len());
-
-            default_len = features.len();
-
-            features.extend(remaining.into_iter().rev());
-            features
-        });
+
+    if let Some(raw) = row.get(0) {
+        let result = order_features_and_count_default_len(raw);
+        features = Some(result.0);
+        default_len = result.1;
+    }
 
     FeaturesPage {
         metadata: cexpect!(req, MetaData::from_crate(&mut conn, &name, &version)),
@@ -69,11 +57,26 @@ pub fn build_features_handler(req: &mut Request) -> IronResult<Response> {
     .into_response(req)
 }
 
+fn order_features_and_count_default_len(raw: Vec<Feature>) -> (Vec<Feature>, usize) {
+    let mut feature_map = get_feature_map(raw);
+    let mut features = get_tree_structure_from_default(&mut feature_map);
+    let mut remaining: Vec<_> = feature_map
+        .into_iter()
+        .map(|(_, feature)| feature)
+        .collect();
+    remaining.sort_by_key(|feature| feature.subfeatures.len());
+
+    let default_len = features.len();
+
+    features.extend(remaining.into_iter().rev());
+    (features, default_len)
+}
+
 fn get_tree_structure_from_default(feature_map: &mut HashMap<String, Feature>) -> Vec<Feature> {
     let mut features = Vec::new();
     let mut queue: VecDeque<String> = VecDeque::new();
 
-    queue.push_back("default".into());
+    queue.push_back(DEFAULT_NAME.into());
     while !queue.is_empty() {
         let name = queue.pop_front().unwrap();
         if let Some(feature) = feature_map.remove(&name) {
@@ -86,3 +89,132 @@ fn get_tree_structure_from_default(feature_map: &mut HashMap<String, Feature>) -
     }
     features
 }
+
+fn get_feature_map(raw: Vec<Feature>) -> HashMap<String, Feature> {
+    raw.into_iter()
+        .filter(|feature| !feature.is_private())
+        .map(|feature| (feature.name.clone(), feature))
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::db::types::Feature;
+    use crate::web::features::{
+        get_feature_map, get_tree_structure_from_default, order_features_and_count_default_len,
+        DEFAULT_NAME,
+    };
+
+    #[test]
+    fn test_feature_map_filters_private() {
+        let private1 = Feature::new("_private1".into(), vec!["feature1".into()]);
+        let feature2 = Feature::new("feature2".into(), Vec::new());
+
+        let raw = vec![private1.clone(), feature2.clone()];
+        let feature_map = get_feature_map(raw);
+
+        assert_eq!(feature_map.len(), 1);
+        assert!(feature_map.contains_key(&feature2.name));
+        assert!(!feature_map.contains_key(&private1.name));
+    }
+
+    #[test]
+    fn test_default_tree_structure_with_nested_default() {
+        let default = Feature::new(DEFAULT_NAME.into(), vec!["feature1".into()]);
+        let non_default = Feature::new("non-default".into(), Vec::new());
+        let feature1 = Feature::new(
+            "feature1".into(),
+            vec!["feature2".into(), "feature3".into()],
+        );
+        let feature2 = Feature::new("feature2".into(), Vec::new());
+        let feature3 = Feature::new("feature3".into(), Vec::new());
+
+        let raw = vec![
+            default.clone(),
+            non_default.clone(),
+            feature3.clone(),
+            feature2.clone(),
+            feature1.clone(),
+        ];
+        let mut feature_map = get_feature_map(raw);
+        let default_tree = get_tree_structure_from_default(&mut feature_map);
+
+        assert_eq!(feature_map.len(), 1);
+        assert_eq!(default_tree.len(), 4);
+        assert!(feature_map.contains_key(&non_default.name));
+        assert!(!feature_map.contains_key(&default.name));
+        assert_eq!(default_tree[0], default);
+        assert_eq!(default_tree[1], feature1);
+        assert_eq!(default_tree[2], feature2);
+        assert_eq!(default_tree[3], feature3);
+    }
+
+    #[test]
+    fn test_default_tree_structure_without_default() {
+        let feature1 = Feature::new(
+            "feature1".into(),
+            vec!["feature2".into(), "feature3".into()],
+        );
+        let feature2 = Feature::new("feature2".into(), Vec::new());
+        let feature3 = Feature::new("feature3".into(), Vec::new());
+
+        let raw = vec![feature3.clone(), feature2.clone(), feature1.clone()];
+        let mut feature_map = get_feature_map(raw);
+        let default_tree = get_tree_structure_from_default(&mut feature_map);
+
+        assert_eq!(feature_map.len(), 3);
+        assert_eq!(default_tree.len(), 0);
+        assert!(feature_map.contains_key(&feature1.name));
+        assert!(feature_map.contains_key(&feature2.name));
+        assert!(feature_map.contains_key(&feature3.name));
+    }
+
+    #[test]
+    fn test_default_tree_structure_single_default() {
+        let default = Feature::new(DEFAULT_NAME.into(), Vec::new());
+        let non_default = Feature::new("non-default".into(), Vec::new());
+
+        let raw = vec![default.clone(), non_default.clone()];
+        let mut feature_map = get_feature_map(raw);
+        let default_tree = get_tree_structure_from_default(&mut feature_map);
+
+        assert_eq!(feature_map.len(), 1);
+        assert_eq!(default_tree.len(), 1);
+        assert!(feature_map.contains_key(&non_default.name));
+        assert!(!feature_map.contains_key(&default.name));
+        assert_eq!(default_tree[0], default);
+    }
+
+    #[test]
+    fn test_order_features_and_get_len_without_default() {
+        let feature1 = Feature::new(
+            "feature1".into(),
+            vec!["feature10".into(), "feature11".into()],
+        );
+        let feature2 = Feature::new("feature2".into(), vec!["feature20".into()]);
+        let feature3 = Feature::new("feature3".into(), Vec::new());
+
+        let raw = vec![feature3.clone(), feature2.clone(), feature1.clone()];
+        let (features, default_len) = order_features_and_count_default_len(raw);
+
+        assert_eq!(features.len(), 3);
+        assert_eq!(default_len, 0);
+        assert_eq!(features[0], feature1);
+        assert_eq!(features[1], feature2);
+        assert_eq!(features[2], feature3);
+    }
+
+    #[test]
+    fn test_order_features_and_get_len_single_default() {
+        let default = Feature::new(DEFAULT_NAME.into(), Vec::new());
+        let non_default = Feature::new("non-default".into(), Vec::new());
+
+        let raw = vec![default.clone(), non_default.clone()];
+        let (features, default_len) = order_features_and_count_default_len(raw);
+
+        assert_eq!(features.len(), 2);
+        assert_eq!(default_len, 1);
+        assert_eq!(features[0], default);
+        assert_eq!(features[1], non_default);
+    }
+}