From 55653ff0f38e7342a863a9e01189f3a5899ba598 Mon Sep 17 00:00:00 2001
From: Garrit Franke <garritfranke@gmail.com>
Date: Fri, 4 Dec 2020 10:36:37 +0100
Subject: [PATCH] Add parser tests

---
 src/parser/mod.rs   |  5 +++-
 src/parser/tests.rs | 56 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 src/parser/tests.rs

diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index a16f8fa..7456b62 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -6,6 +6,9 @@ use std::vec::IntoIter;
 
 mod node_type;
 
+#[cfg(test)]
+mod tests;
+
 pub struct Parser {
     tokens: Peekable<IntoIter<Token>>,
     peeked: Vec<Token>,
@@ -108,7 +111,7 @@ impl Parser {
         let globals = Vec::new();
 
         while self.has_more() {
-            functions.push(self.parse_function().expect("Failed to parse function"))
+            functions.push(self.parse_function()?)
         }
 
         Ok(Program {
diff --git a/src/parser/tests.rs b/src/parser/tests.rs
new file mode 100644
index 0000000..508a2c1
--- /dev/null
+++ b/src/parser/tests.rs
@@ -0,0 +1,56 @@
+use crate::lexer::*;
+use crate::parser::*;
+
+#[test]
+fn test_parse_empty_function() {
+    let tokens = tokenize("fn main() {}");
+    let tree = parse(tokens);
+    assert!(tree.is_ok())
+}
+
+#[test]
+fn test_parse_function_with_return() {
+    let raw = "
+    fn main() {
+        return 1;
+    }
+    ";
+    let tokens = tokenize(raw);
+    let tree = parse(tokens);
+    assert!(tree.is_ok())
+}
+
+#[test]
+fn test_parse_missing_semicolon() {
+    let raw = "
+    fn main() {
+        return 1
+    }
+    ";
+    let tokens = tokenize(raw);
+    let tree = parse(tokens);
+    assert!(tree.is_err())
+}
+
+#[test]
+fn test_parse_no_function_context() {
+    let raw = "
+    let x = 1;
+    ";
+    let tokens = tokenize(raw);
+    let tree = parse(tokens);
+    assert!(tree.is_err())
+}
+
+#[test]
+fn test_parse_variable_declaration() {
+    let raw = "
+    fn main() {
+        let x = 1;
+        return x;
+    }
+    ";
+    let tokens = tokenize(raw);
+    let tree = parse(tokens);
+    assert!(tree.is_ok())
+}