add parser tests

src/tests/bom.rs

@@ -0,0 +1,37 @@
+use crate::atom_table::*;
+use crate::parser::ast::*;
+use crate::parser::lexer::{Lexer, Token};
+
+#[test]
+fn valid_token() {
+    let stream = parsing_stream("valid text".as_bytes());
+    assert!(stream.is_ok());
+}
+
+#[test]
+fn empty_stream() {
+    let bytes: &[u8] = &[];
+    assert!(parsing_stream(bytes).is_ok());
+}
+
+#[test]
+fn skip_utf8_bom() {
+    let mut machine_st = MachineState::new();
+    let bytes: &[u8] = &[0xEF, 0xBB, 0xBF, '4' as u8, '\n' as u8];
+    let stream = parsing_stream(bytes).expect("valid stream");
+    let mut lexer = Lexer::new(stream, &mut machine_st);
+    match lexer.next_token() {
+        Ok(Token::Literal(Literal::Fixnum(Fixnum::build_with(4)))) => (),
+        _ => assert!(false),
+    }
+}
+
+#[test]
+fn invalid_utf16_bom() {
+    let bytes: &[u8] = &[0xFF, 0xFE, 'a' as u8, '\n' as u8];
+    let stream = parsing_stream(bytes);
+    match stream {
+        Err(ParserError::Utf8Error(0, 0)) => (),
+        _ => assert!(false),
+    }
+}