Auto merge of #119 - matthiasbeyer:libimagutil-init, r=matthiasbeyer

Libimagutil init

Extracted from #89

libimagutil/src/lib.rs

@@ -1,3 +1 @@
-#[test]
+pub mod variants;
-fn it_works() {
-}

libimagutil/src/variants.rs

@@ -0,0 +1,59 @@
+/**
+ * Generate variants of a base value by applying parts
+ *
+ * Example:
+ *
+ * ```ignore
+ * generate_variants(path, vec!["foo", "bar", "baz"], |b, v| {
+ *    let b = b.clone();
+ *    b.push(v);
+ *    b
+ * })
+ *
+ * ```
+ *
+ */
+pub fn generate_variants<A, B, C, F>(base: A, modders: Vec<B>, f: &F)
+    -> Vec<C>
+    where
+        F: Fn(&A, B) -> C
+{
+    modders.into_iter().map(|m| f(&base, m)).collect()
+}
+
+#[cfg(test)]
+mod test {
+
+    use super::generate_variants;
+
+    #[test]
+    fn test_variants_simple() {
+        let base = 1;
+        let vars = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+        let res = generate_variants(base, vars, &|base, var| base + var);
+
+        assert!(res.len() == 11, format!("Length is {} instead of 11", res.len()));
+        assert!(res.iter().all(|i| *i > 0));
+        assert!(res == vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11])
+    }
+
+    #[test]
+    fn test_variants_pathes() {
+        use std::path::PathBuf;
+
+        let base = PathBuf::from("/");
+        let vars = vec!["foo", "bar", "baz"];
+        let res = generate_variants(base, vars, &|base, var| {
+            let mut base = base.clone();
+            base.push(var);
+            base
+        });
+
+        assert!(res.len() == 3, format!("Length is {} instead of 3", res.len()));
+        let eq_vec = vec!["/foo", "/bar", "/baz"];
+        let eq     = eq_vec.iter().map(PathBuf::from);
+        assert!(res.into_iter().zip(eq).all(|(orig, equi)| orig == equi));
+    }
+
+}
+