Rust: Additional test cases exposing what works and what doesn't.

Author: geoffw0

rust/ql/test/library-tests/dataflow/sources/TaintSources.expected

@@ -19,5 +19,6 @@
 | test.rs:72:26:72:37 | ...::get | Flow source 'RemoteSource' of type remote (DEFAULT). |
 | test.rs:75:26:75:37 | ...::get | Flow source 'RemoteSource' of type remote (DEFAULT). |
 | test.rs:78:24:78:35 | ...::get | Flow source 'RemoteSource' of type remote (DEFAULT). |
-| test.rs:108:31:108:42 | send_request | Flow source 'RemoteSource' of type remote (DEFAULT). |
-| test.rs:192:16:192:29 | ...::args | Flow source 'CommandLineArgs' of type commandargs. |
+| test.rs:110:35:110:46 | send_request | Flow source 'RemoteSource' of type remote (DEFAULT). |
+| test.rs:117:31:117:42 | send_request | Flow source 'RemoteSource' of type remote (DEFAULT). |
+| test.rs:201:16:201:29 | ...::args | Flow source 'CommandLineArgs' of type commandargs. |

rust/ql/test/library-tests/dataflow/sources/test.rs

@@ -104,9 +104,18 @@ async fn test_hyper_http(case: i64) -> Result<(), Box<dyn std::error::Error>> {
 
     // make the request
     println!("sending request...");
+    if (case == 0) {
+        // simple flow case
+        let request = http::Request::builder().uri(url).body(String::from(""))?;
+        let mut response = sender.send_request(request).await?; // $ Alert[rust/summary/taint-sources]
+        sink(&response); // $ hasTaintFlow=request
+        sink(response); // $ hasTaintFlow=request
+        return Ok(())
+    }
+    // more realistic uses of results...
     let request = http::Request::builder().uri(url).body(String::from(""))?;
     let mut response = sender.send_request(request).await?; // $ Alert[rust/summary/taint-sources]
-    sink(&response); // $ MISSING: hasTaintFlow
+    sink(&response); // $ MISSING: hasTaintFlow=request
 
     if !response.status().is_success() {
         return Err("request failed".into())