From a8bf78eb241e2c8770e3ab7fb5dc579766a4ea11 Mon Sep 17 00:00:00 2001
From: Putta Khunchalee <ultimaweapon@outlook.com>
Date: Fri, 12 Apr 2024 23:52:22 +0700
Subject: [PATCH] Adds tests

---
 .github/workflows/ci.yml |  2 ++
 Cargo.toml               |  3 +++
 src/lib.rs               | 30 ++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 54073e9..03889c3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,3 +17,5 @@ jobs:
       run: cargo fmt --check
     - name: Lint
       run: cargo clippy -- -D warnings
+    - name: Run tests
+      run: cargo test --workspace
diff --git a/Cargo.toml b/Cargo.toml
index eb52397..b75acb5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,3 +7,6 @@ repository = "https://github.com/ultimaweapon/erdp"
 edition = "2021"
 
 [dependencies]
+
+[dev-dependencies]
+thiserror = "1.0.58"
diff --git a/src/lib.rs b/src/lib.rs
index 00ac262..d153ac2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -35,3 +35,33 @@ impl<'a> std::fmt::Display for Display<'a> {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use thiserror::Error;
+
+    #[test]
+    fn single() {
+        let e = TestError::Single;
+
+        assert_eq!(e.display().to_string(), "an error without nested errors");
+    }
+
+    #[test]
+    fn nested() {
+        let e = std::io::Error::from(std::io::ErrorKind::NotFound);
+        let e = TestError::Nested(e);
+
+        assert_eq!(e.display().to_string(), "nested error -> entity not found");
+    }
+
+    #[derive(Debug, Error)]
+    enum TestError {
+        #[error("an error without nested errors")]
+        Single,
+
+        #[error("nested error")]
+        Nested(#[source] std::io::Error),
+    }
+}