Improve test coverage (#1490)

Improve test coverage

libsqlite3-sys/src/error.rs

@@ -302,3 +302,42 @@ impl ::std::fmt::Display for InitError {
 }
 #[cfg(feature = "loadable_extension")]
 impl error::Error for InitError {}
+
+#[cfg(test)]
+mod test {
+    use crate::*;
+
+    #[test]
+    pub fn error_new() {
+        let assoc = vec![
+            (SQLITE_INTERNAL, ErrorCode::InternalMalfunction),
+            (SQLITE_PERM, ErrorCode::PermissionDenied),
+            (SQLITE_ABORT_ROLLBACK, ErrorCode::OperationAborted),
+            (SQLITE_BUSY_RECOVERY, ErrorCode::DatabaseBusy),
+            (SQLITE_LOCKED_SHAREDCACHE, ErrorCode::DatabaseLocked),
+            (SQLITE_NOMEM, ErrorCode::OutOfMemory),
+            (SQLITE_IOERR_READ, ErrorCode::SystemIoFailure),
+            (SQLITE_NOTFOUND, ErrorCode::NotFound),
+            (SQLITE_FULL, ErrorCode::DiskFull),
+            (SQLITE_PROTOCOL, ErrorCode::FileLockingProtocolFailed),
+            (SQLITE_SCHEMA, ErrorCode::SchemaChanged),
+            (SQLITE_TOOBIG, ErrorCode::TooBig),
+            (SQLITE_MISMATCH, ErrorCode::TypeMismatch),
+            (SQLITE_NOLFS, ErrorCode::NoLargeFileSupport),
+            (SQLITE_RANGE, ErrorCode::ParameterOutOfRange),
+            (SQLITE_NOTADB, ErrorCode::NotADatabase),
+        ];
+        for (sqlite_code, rust_code) in assoc {
+            let err = Error::new(sqlite_code);
+            assert_eq!(
+                err,
+                Error {
+                    code: rust_code,
+                    extended_code: sqlite_code
+                }
+            );
+            let s = format!("{}", err);
+            assert!(!s.is_empty());
+        }
+    }
+}