Improve test coverage

src/lib.rs

@@ -192,56 +192,3 @@ pub fn decode(input: &[u16], output: &mut [u8]) -> Result<usize> {
         Ok(())
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn encoding() {
-        let input = "őэ╋";
-        let mut buffer = [0u16; 3];
-
-        let result = encode(input, &mut buffer);
-        assert_eq!(result.unwrap(), 3);
-
-        assert_eq!(buffer[..], [0x0151, 0x044D, 0x254B]);
-    }
-
-    #[test]
-    fn decoding() {
-        let input = "$¢ह한";
-        let mut u16_buffer = [0u16; 4];
-        let result = encode(input, &mut u16_buffer);
-        assert_eq!(result.unwrap(), 4);
-
-        let mut u8_buffer = [0u8; 9];
-        let result = decode(&u16_buffer, &mut u8_buffer);
-        assert_eq!(result.unwrap(), 9);
-        assert_eq!(core::str::from_utf8(&u8_buffer[0..9]), Ok("$¢ह한"));
-    }
-
-    #[test]
-    fn decoding_with() {
-        let input = "$¢ह한";
-
-        let mut u16_buffer = [0u16; 4];
-        let result = encode(input, &mut u16_buffer);
-        assert_eq!(result.unwrap(), 4);
-
-        let mut u8_buffer = [0u8; 9];
-        let mut pos = 0;
-
-        let result = decode_with(&u16_buffer, |bytes| {
-            for byte in bytes.into_iter() {
-                u8_buffer[pos] = *byte;
-                pos += 1;
-            }
-
-            Ok(())
-        });
-
-        assert_eq!(result.unwrap(), 9);
-        assert_eq!(core::str::from_utf8(&u8_buffer[0..9]), Ok("$¢ह한"));
-    }
-}

tests/tests.rs

@@ -0,0 +1,66 @@
+use ucs2::{decode, decode_with, encode, Error};
+
+#[test]
+fn encoding() {
+    let input = "őэ╋";
+    let mut buffer = [0u16; 3];
+
+    assert_eq!(encode(input, &mut buffer), Ok(3));
+    assert_eq!(buffer[..], [0x0151, 0x044D, 0x254B]);
+
+    let mut buffer = [0u16; 2];
+    assert_eq!(encode(input, &mut buffer), Err(Error::BufferOverflow));
+
+    let input = "😎";
+    assert_eq!(encode(input, &mut buffer), Err(Error::MultiByte));
+}
+
+#[test]
+fn decoding() {
+    let input = "$¢ह한";
+    let mut u16_buffer = [0u16; 4];
+    assert_eq!(encode(input, &mut u16_buffer), Ok(4));
+
+    let mut u8_buffer = [0u8; 9];
+    assert_eq!(decode(&u16_buffer, &mut u8_buffer), Ok(9));
+    assert_eq!(core::str::from_utf8(&u8_buffer[0..9]), Ok("$¢ह한"));
+
+    // `decode` has three branches that can return `BufferOverflow`,
+    // check each of them.
+    assert_eq!(
+        decode(&u16_buffer, &mut u8_buffer[..0]),
+        Err(Error::BufferOverflow)
+    );
+    assert_eq!(
+        decode(&u16_buffer, &mut u8_buffer[..1]),
+        Err(Error::BufferOverflow)
+    );
+    assert_eq!(
+        decode(&u16_buffer, &mut u8_buffer[..3]),
+        Err(Error::BufferOverflow)
+    );
+}
+
+#[test]
+fn decoding_with() {
+    let input = "$¢ह한";
+
+    let mut u16_buffer = [0u16; 4];
+    let result = encode(input, &mut u16_buffer);
+    assert_eq!(result.unwrap(), 4);
+
+    let mut u8_buffer = [0u8; 9];
+    let mut pos = 0;
+
+    let result = decode_with(&u16_buffer, |bytes| {
+        for byte in bytes.into_iter() {
+            u8_buffer[pos] = *byte;
+            pos += 1;
+        }
+
+        Ok(())
+    });
+
+    assert_eq!(result.unwrap(), 9);
+    assert_eq!(core::str::from_utf8(&u8_buffer[0..9]), Ok("$¢ह한"));
+}