1 files changed, 50 insertions, 0 deletions

diff --git a/tools/src/lib.rs b/tools/src/lib.rs
new file mode 100644
index 000000000..157818bdf
--- /dev/null
+++ b/tools/src/lib.rs
@@ -0,0 +1,50 @@
+extern crate itertools;
+use itertools::Itertools;
+
+#[derive(Debug, Eq)]
+pub struct Test {
+    pub start_line: usize,
+    pub name: String,
+    pub text: String,
+}
+
+impl PartialEq for Test {
+    fn eq(&self, other: &Test) -> bool {
+        self.name.eq(&other.name)
+    }
+}
+
+pub fn collect_tests(s: &str) -> Vec<Test> {
+    let mut res = vec![];
+    let prefix = "// ";
+    let comment_blocks = s
+        .lines()
+        .map(str::trim_left)
+        .enumerate()
+        .group_by(|(idx, line)| line.starts_with(prefix));
+
+    'outer: for (is_comment, block) in comment_blocks.into_iter() {
+        if !is_comment {
+            continue;
+        }
+        let mut block = block.map(|(idx, line)| (idx, &line[prefix.len()..]));
+
+        let (start_line, name) = loop {
+            match block.next() {
+                Some((idx, line)) if line.starts_with("test ") => {
+                    break (idx, line["test ".len()..].to_string())
+                },
+                Some(_) => (),
+                None => continue 'outer,
+            }
+        };
+        let text: String = itertools::join(
+            block.map(|(_, line)| line)
+                .chain(::std::iter::once("")),
+            "\n"
+        );
+        assert!(!text.trim().is_empty() && text.ends_with("\n"));
+        res.push(Test { start_line, name, text })
+    }
+    res
+}