Add support for using testserver in doctests. (#218)

Doctests run against a normally-built copy of the crate, i.e. one
without #[cfg(test)] set, so we can't use the conditional compilation
feature.

Instead, define a static var that indicates whether the library is
running in test mode or not. For each doctest, insert a hidden call that
sets this var to true. Then, when ureq::agent() is called, it returns a
test_agent instead.

This required moving testserver out of the test mod and into src/, so
that it can be included unconditionally (i.e. when cfg(test) is false).

This PR converts one doctest as an example. If we land this PR, I'll
send a followup to convert the rest.

src/lib.rs

@@ -121,6 +121,8 @@ pub use serde_json::json;
 
 #[cfg(test)]
 mod test;
+#[doc(hidden)]
+mod testserver;
 
 pub use crate::agent::Agent;
 pub use crate::agent::AgentBuilder;
@@ -137,17 +139,41 @@ pub use cookie::Cookie;
 #[cfg(feature = "json")]
 pub use serde_json::{to_value as serde_to_value, Map as SerdeMap, Value as SerdeValue};
 
+use once_cell::sync::Lazy;
+use std::sync::atomic::{AtomicBool, Ordering};
+
 /// Creates an agent builder.
 pub fn builder() -> AgentBuilder {
     AgentBuilder::new()
 }
 
+// is_test returns false so long as it has only ever been called with false.
+// If it has ever been called with true, it will always return true after that.
+// This is a public but hidden function used to allow doctests to use the test_agent.
+// Note that we use this approach for doctests rather the #[cfg(test)], because
+// doctests are run against a copy of the crate build without cfg(test) set.
+// We also can't use #[cfg(doctest)] to do this, because cfg(doctest) is only set
+// when collecting doctests, not when building the crate.
+#[doc(hidden)]
+pub fn is_test(is: bool) -> bool {
+    static IS_TEST: Lazy<AtomicBool> = Lazy::new(|| AtomicBool::new(false));
+    if is {
+        IS_TEST.store(true, Ordering::SeqCst);
+    }
+    let x = IS_TEST.load(Ordering::SeqCst);
+    return x;
+}
+
 /// Agents are used to keep state between requests.
 pub fn agent() -> Agent {
     #[cfg(not(test))]
-    return AgentBuilder::new().build();
+    if is_test(false) {
+        return testserver::test_agent();
+    } else {
+        return AgentBuilder::new().build();
+    }
     #[cfg(test)]
-    return test::test_agent();
+    return testserver::test_agent();
 }
 
 /// Make a request setting the HTTP method via a string.

src/request.rs

@@ -103,14 +103,12 @@ impl Request {
     /// The `Content-Length` header is implicitly set to the length of the serialized value.
     ///
     /// ```
-    /// #[macro_use]
-    /// extern crate ureq;
-    ///
-    /// fn main() {
-    /// let r = ureq::post("/my_page")
-    ///     .send_json(json!({ "name": "martin", "rust": true }));
-    /// println!("{:?}", r);
-    /// }
+    /// # fn main() -> Result<(), ureq::Error> {
+    /// # ureq::is_test(true);
+    /// let r = ureq::post("http://example.com/form")
+    ///     .send_json(ureq::json!({ "name": "martin", "rust": true }))?;
+    /// # Ok(())
+    /// # }
     /// ```
     #[cfg(feature = "json")]
     pub fn send_json(mut self, data: SerdeValue) -> Result<Response> {

src/test/agent_test.rs

@@ -1,6 +1,6 @@
 #![allow(dead_code)]
 
-use crate::test::testserver::{read_headers, TestServer};
+use crate::testserver::{read_headers, TestServer};
 use std::io::{self, Read, Write};
 use std::net::TcpStream;
 use std::time::Duration;

src/test/mod.rs

@@ -1,10 +1,10 @@
 use crate::unit::Unit;
-use crate::{error::Error, Agent};
-use crate::{stream::Stream, AgentBuilder};
+use crate::{error::Error};
+use crate::{stream::Stream};
 use once_cell::sync::Lazy;
 use std::io::{Cursor, Write};
 use std::sync::{Arc, Mutex};
-use std::{collections::HashMap, net::ToSocketAddrs};
+use std::{collections::HashMap};
 
 mod agent_test;
 mod body_read;
@@ -13,44 +13,8 @@ mod query_string;
 mod range;
 mod redirect;
 mod simple;
-pub(crate) mod testserver;
 mod timeout;
 
-// An agent to be installed by default for tests and doctests, such
-// that all hostnames resolve to a TestServer on localhost.
-pub(crate) fn test_agent() -> Agent {
-    use std::io;
-    use std::net::{SocketAddr, TcpStream};
-    let testserver = testserver::TestServer::new(|mut stream: TcpStream| -> io::Result<()> {
-        testserver::read_headers(&stream);
-        stream.write_all(b"HTTP/1.1 200 OK\r\n")?;
-        stream.write_all(b"Transfer-Encoding: chunked\r\n")?;
-        stream.write_all(b"Content-Type: text/html; charset=ISO-8859-1\r\n")?;
-        stream.write_all(b"\r\n")?;
-        stream.write_all(b"7\r\n")?;
-        stream.write_all(b"success\r\n")?;
-        stream.write_all(b"0\r\n")?;
-        stream.write_all(b"\r\n")?;
-        Ok(())
-    });
-    // Slightly tricky thing here: we want to make sure the TestServer lives
-    // as long as the agent. This is accomplished by `move`ing it into the
-    // closure, which becomes owned by the agent.
-    AgentBuilder::new()
-        .resolver(move |h: &str| -> io::Result<Vec<SocketAddr>> {
-            // Don't override resolution for HTTPS requests yet, since we
-            // don't have a setup for an HTTPS testserver. Also, skip localhost
-            // resolutions since those may come from a unittest that set up
-            // its own, specific testserver.
-            if h.ends_with(":443") || h.starts_with("localhost:") {
-                return Ok(h.to_socket_addrs()?.collect::<Vec<_>>());
-            }
-            let addr: SocketAddr = format!("127.0.0.1:{}", testserver.port).parse().unwrap();
-            Ok(vec![addr])
-        })
-        .build()
-}
-
 type RequestHandler = dyn Fn(&Unit) -> Result<Stream, Error> + Send + 'static;
 
 pub(crate) static TEST_HANDLERS: Lazy<Arc<Mutex<HashMap<String, Box<RequestHandler>>>>> =

src/test/redirect.rs

@@ -2,7 +2,7 @@ use std::{
     io::{self, Write},
     net::TcpStream,
 };
-use test::testserver::{self, TestServer};
+use testserver::{self, TestServer};
 
 use crate::test;
 

src/test/testserver.rs

@@ -1,80 +0,0 @@
-use std::io::{self, BufRead, BufReader};
-use std::net::{TcpListener, TcpStream};
-use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::Arc;
-use std::thread;
-
-pub struct TestServer {
-    pub port: u16,
-    pub done: Arc<AtomicBool>,
-}
-
-pub struct TestHeaders(Vec<String>);
-
-impl TestHeaders {
-    // Return the path for a request, e.g. /foo from "GET /foo HTTP/1.1"
-    #[cfg(feature = "cookies")]
-    pub fn path(&self) -> &str {
-        if self.0.len() == 0 {
-            ""
-        } else {
-            &self.0[0].split(" ").nth(1).unwrap()
-        }
-    }
-
-    #[cfg(feature = "cookies")]
-    pub fn headers(&self) -> &[String] {
-        &self.0[1..]
-    }
-}
-
-// Read a stream until reaching a blank line, in order to consume
-// request headers.
-pub fn read_headers(stream: &TcpStream) -> TestHeaders {
-    let mut results = vec![];
-    for line in BufReader::new(stream).lines() {
-        match line {
-            Err(e) => {
-                eprintln!("testserver: in read_headers: {}", e);
-                break;
-            }
-            Ok(line) if line == "" => break,
-            Ok(line) => results.push(line),
-        };
-    }
-    TestHeaders(results)
-}
-
-impl TestServer {
-    pub fn new(handler: fn(TcpStream) -> io::Result<()>) -> Self {
-        let listener = TcpListener::bind("localhost:0").unwrap();
-        let port = listener.local_addr().unwrap().port();
-        let done = Arc::new(AtomicBool::new(false));
-        let done_clone = done.clone();
-        thread::spawn(move || {
-            for stream in listener.incoming() {
-                if let Err(e) = stream {
-                    eprintln!("testserver: handling just-accepted stream: {}", e);
-                    break;
-                }
-                if done.load(Ordering::SeqCst) {
-                    break;
-                } else {
-                    thread::spawn(move || handler(stream.unwrap()));
-                }
-            }
-        });
-        TestServer {
-            port,
-            done: done_clone,
-        }
-    }
-}
-
-impl Drop for TestServer {
-    fn drop(&mut self) {
-        self.done.store(true, Ordering::SeqCst);
-        // Connect once to unblock the listen loop.
-        TcpStream::connect(format!("localhost:{}", self.port)).unwrap();
-    }
-}

src/test/timeout.rs

@@ -1,4 +1,4 @@
-use crate::test::testserver::*;
+use crate::testserver::*;
 use std::io::{self, Write};
 use std::net::TcpStream;
 use std::thread;

src/testserver.rs

@@ -0,0 +1,137 @@
+use std::net::{SocketAddr, TcpListener, TcpStream};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Arc;
+use std::thread;
+use std::time::Duration;
+use std::{
+    io::{self, BufRead, BufReader, Write},
+    net::ToSocketAddrs,
+};
+
+use crate::{Agent, AgentBuilder};
+
+// An agent to be installed by default for tests and doctests, such
+// that all hostnames resolve to a TestServer on localhost.
+pub(crate) fn test_agent() -> Agent {
+    let testserver = TestServer::new(|mut stream: TcpStream| -> io::Result<()> {
+        read_headers(&stream);
+        stream.write_all(b"HTTP/1.1 200 OK\r\n")?;
+        stream.write_all(b"Transfer-Encoding: chunked\r\n")?;
+        stream.write_all(b"Content-Type: text/html; charset=ISO-8859-1\r\n")?;
+        stream.write_all(b"\r\n")?;
+        stream.write_all(b"7\r\n")?;
+        stream.write_all(b"success\r\n")?;
+        stream.write_all(b"0\r\n")?;
+        stream.write_all(b"\r\n")?;
+        Ok(())
+    });
+    // Slightly tricky thing here: we want to make sure the TestServer lives
+    // as long as the agent. This is accomplished by `move`ing it into the
+    // closure, which becomes owned by the agent.
+    AgentBuilder::new()
+        .resolver(move |h: &str| -> io::Result<Vec<SocketAddr>> {
+            // Don't override resolution for HTTPS requests yet, since we
+            // don't have a setup for an HTTPS testserver. Also, skip localhost
+            // resolutions since those may come from a unittest that set up
+            // its own, specific testserver.
+            if h.ends_with(":443") || h.starts_with("localhost:") {
+                return Ok(h.to_socket_addrs()?.collect::<Vec<_>>());
+            }
+            let addr: SocketAddr = format!("127.0.0.1:{}", testserver.port).parse().unwrap();
+            Ok(vec![addr])
+        })
+        .build()
+}
+
+pub struct TestServer {
+    pub port: u16,
+    pub done: Arc<AtomicBool>,
+}
+
+pub struct TestHeaders(Vec<String>);
+
+#[allow(dead_code)]
+impl TestHeaders {
+    // Return the path for a request, e.g. /foo from "GET /foo HTTP/1.1"
+    #[cfg(feature = "cookies")]
+    pub fn path(&self) -> &str {
+        if self.0.len() == 0 {
+            ""
+        } else {
+            &self.0[0].split(" ").nth(1).unwrap()
+        }
+    }
+
+    #[cfg(feature = "cookies")]
+    pub fn headers(&self) -> &[String] {
+        &self.0[1..]
+    }
+}
+
+// Read a stream until reaching a blank line, in order to consume
+// request headers.
+pub fn read_headers(stream: &TcpStream) -> TestHeaders {
+    let mut results = vec![];
+    for line in BufReader::new(stream).lines() {
+        match line {
+            Err(e) => {
+                eprintln!("testserver: in read_headers: {}", e);
+                break;
+            }
+            Ok(line) if line == "" => break,
+            Ok(line) => results.push(line),
+        };
+    }
+    TestHeaders(results)
+}
+
+impl TestServer {
+    pub fn new(handler: fn(TcpStream) -> io::Result<()>) -> Self {
+        let listener = TcpListener::bind("127.0.0.1:0").unwrap();
+        let port = listener.local_addr().unwrap().port();
+        let done = Arc::new(AtomicBool::new(false));
+        let done_clone = done.clone();
+        thread::spawn(move || {
+            for stream in listener.incoming() {
+                if let Err(e) = stream {
+                    eprintln!("testserver: handling just-accepted stream: {}", e);
+                    break;
+                }
+                if done.load(Ordering::SeqCst) {
+                    break;
+                } else {
+                    thread::spawn(move || handler(stream.unwrap()));
+                }
+            }
+        });
+        // before returning from new(), ensure the server is ready to accept connections
+        loop {
+            if let Err(e) = TcpStream::connect(format!("127.0.0.1:{}", port)) {
+                match e.kind() {
+                    io::ErrorKind::ConnectionRefused => {
+                        std::thread::sleep(Duration::from_millis(100));
+                        continue;
+                    }
+                    _ => eprintln!("testserver: pre-connect with error {}", e),
+                }
+            } else {
+                break;
+            }
+        }
+        TestServer {
+            port,
+            done: done_clone,
+        }
+    }
+}
+
+impl Drop for TestServer {
+    fn drop(&mut self) {
+        self.done.store(true, Ordering::SeqCst);
+        // Connect once to unblock the listen loop.
+        match TcpStream::connect(format!("localhost:{}", self.port)) {
+            Err(e) => eprintln!("error dropping testserver: {}", e),
+            _ => {}
+        }
+    }
+}