Auto merge of #392 - frewsxcv:frewsxcv-roundtrip, r=mbrubeck

Extend fuzz target to also do serialization.

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Author: bors-servo

fuzz/Cargo.toml

@@ -15,7 +15,7 @@ git = "https://github.com/rust-fuzz/libfuzzer-sys.git"
 
 [[bin]]
 name = "parse"
-path = "fuzzers/parse.rs"
+path = "fuzz_targets/parse.rs"
 
 [workspace]
 members = ["."]

fuzz/fuzzers/parse.rs renamed to fuzz/fuzz_targets/parse.rs

@@ -5,6 +5,9 @@ use std::str;
 
 fuzz_target!(|data: &[u8]| {
     if let Ok(utf8) = str::from_utf8(data) {
-        let _ = url::Url::parse(utf8);
+        if let Ok(parsed) = url::Url::parse(utf8) {
+            let as_str = parsed.as_str();
+            assert_eq!(parsed, url::Url::parse(as_str).unwrap());
+        }
     }
 });