WIP: Implement Bracket Push

No implementation yet, just getting the tests & stub committed.

exercises/bracket-push/Cargo.toml

@@ -0,0 +1,3 @@
+[package]
+name = "bracket-push"
+version = "0.0.0"

exercises/bracket-push/example.rs

@@ -0,0 +1 @@
+

exercises/bracket-push/src/lib.rs

@@ -0,0 +1,16 @@
+// The code below is a stub. Just enough to satisfy the compiler.
+// In order to pass the tests you can add-to or change any of this code.
+
+pub struct Brackets;
+
+impl<'a> From<&'a str> for Brackets {
+    fn from(i: &str) -> Self {
+        unimplemented!()
+    }
+}
+
+impl Brackets {
+    pub fn are_balanced(&self) -> bool {
+        unimplemented!()
+    }
+}

exercises/bracket-push/tests/bracket-push.rs

@@ -0,0 +1,70 @@
+extern crate bracket_push;
+
+use bracket_push::*;
+
+#[test]
+fn paired_square_brackets() {
+    assert!(Brackets::from("[]").are_balanced());
+}
+
+#[test]
+fn empty_string() {
+    assert!(Brackets::from("").are_balanced());
+}
+
+#[test]
+fn unpaired_brackets() {
+    assert!(!Brackets::from("[[").are_balanced());
+}
+
+#[test]
+fn wrong_ordered_brackets() {
+    assert!(!Brackets::from("}{").are_balanced());
+}
+
+#[test]
+fn paired_with_whitespace() {
+    assert!(Brackets::from("{ }").are_balanced());
+}
+
+#[test]
+fn simple_nested_brackets() {
+    assert!(Brackets::from("{[]}").are_balanced());
+}
+
+#[test]
+fn several_paired_brackets() {
+    assert!(Brackets::from("{}[]").are_balanced());
+}
+
+#[test]
+fn paired_and_nested_brackets() {
+    assert!(Brackets::from("([{}({}[])])").are_balanced());
+}
+
+#[test]
+fn unopened_closing_brackets() {
+    assert!(!Brackets::from("{[)][]}").are_balanced());
+}
+
+#[test]
+fn unpaired_and_nested_brackets() {
+    assert!(!Brackets::from("([{])").are_balanced());
+}
+
+#[test]
+fn paired_and_wrong_nested_brackets() {
+    assert!(!Brackets::from("[({]})").are_balanced());
+}
+
+#[test]
+fn math_expression() {
+    assert!(Brackets::from("(((185 + 223.85) * 15) - 543)/2").are_balanced());
+}
+
+#[test]
+fn complex_latex_expression() {
+    let input = "\\left(\\begin{array}{cc} \\frac{1}{3} & x\\\\ \\mathrm{e}^{x} &... x^2 \
+                 \\end{array}\\right)";
+    assert!(Brackets::from(input).are_balanced());
+}