Add Travis integration testing

This uses [GreenMail's Docker
image](http://www.icegreen.com/greenmail/#deploy_docker_standalone) to
spin up a real SMTP+IMAP server on Travis, and then runs a series of
integration tests against it by sending e-mails using
[`lettre`](https://crates.io/crates/lettre) and checking that we can
receive them correctly.

A start on #101.

.travis.yml

@@ -6,6 +6,9 @@ addons:
     packages:
       - libssl-dev
 
+services:
+- docker
+
 os:
 - linux
 - osx
@@ -23,6 +26,10 @@ script:
  - cargo check --all-targets
  - cargo test
 
+before_install:
+ - docker pull greenmail/standalone:1.5.8
+ - docker run -t -i -e GREENMAIL_OPTS='-Dgreenmail.setup.test.all -Dgreenmail.hostname=0.0.0.0 -Dgreenmail.auth.disabled -Dgreenmail.verbose' -p 3025:3025 -p 3110:3110 -p 3143:3143 -p 3465:3465 -p 3993:3993 -p 3995:3995 greenmail/standalone:1.5.8
+
 after_success:
 - if [[ "$TRAVIS_OS_NAME" == "linux" && "$TRAVIS_RUST_VERSION" == "stable" ]]; then
     bash <(curl https://raw.githubusercontent.com/xd009642/tarpaulin/master/travis-install.sh);

Cargo.toml

@@ -31,3 +31,11 @@ bufstream = "0.1"
 imap-proto = "0.6"
 nom = "4.0"
 base64 = "0.10"
+
+[dev-dependencies]
+lettre = "0.9"
+lettre_email = "0.9"
+
+[patch.crates-io]
+lettre = { git = "https://github.com/lettre/lettre.git" }
+lettre_email = { git = "https://github.com/lettre/lettre.git" }

tests/integration.rs

@@ -0,0 +1,215 @@
+extern crate imap;
+extern crate lettre;
+extern crate lettre_email;
+extern crate native_tls;
+
+use lettre::Transport;
+use std::net::TcpStream;
+
+fn tls() -> native_tls::TlsConnector {
+    native_tls::TlsConnector::builder()
+        .danger_accept_invalid_certs(true)
+        .build()
+        .unwrap()
+}
+
+fn session(user: &str) -> imap::Session<native_tls::TlsStream<TcpStream>> {
+    let mut s = imap::connect("127.0.0.1:3993", "imap.example.com", &tls())
+        .unwrap()
+        .login(user, user)
+        .unwrap();
+    s.debug = true;
+    s
+}
+
+fn smtp(user: &str) -> lettre::SmtpTransport {
+    let creds = lettre::smtp::authentication::Credentials::new(user.to_string(), user.to_string());
+    lettre::SmtpClient::new(
+        "127.0.0.1:3465",
+        lettre::ClientSecurity::Wrapper(lettre::ClientTlsParameters {
+            connector: tls(),
+            domain: "smpt.example.com".to_string(),
+        }),
+    )
+    .unwrap()
+    .credentials(creds)
+    .transport()
+}
+
+#[test]
+fn connect_insecure() {
+    imap::connect_insecure("127.0.0.1:3143").unwrap();
+}
+
+#[test]
+#[ignore]
+fn connect_insecure_then_secure() {
+    // ignored because of https://github.com/greenmail-mail-test/greenmail/issues/135
+    imap::connect_insecure("127.0.0.1:3143")
+        .unwrap()
+        .secure("imap.example.com", &tls())
+        .unwrap();
+}
+
+#[test]
+fn connect_secure() {
+    imap::connect("127.0.0.1:3993", "imap.example.com", &tls()).unwrap();
+}
+
+#[test]
+fn login() {
+    session("readonly-test@localhost");
+}
+
+#[test]
+fn logout() {
+    let mut s = session("readonly-test@localhost");
+    s.logout().unwrap();
+}
+
+#[test]
+#[ignore]
+fn inbox_zero() {
+    // https://github.com/djc/tokio-imap/issues/34
+    let mut s = session("readonly-test@localhost");
+    s.select("INBOX").unwrap();
+    let inbox = s.search("ALL").unwrap();
+    assert_eq!(inbox.len(), 0);
+}
+
+#[test]
+fn inbox() {
+    let to = "inbox@localhost";
+
+    // first log in so we'll see the unsolicited e-mails
+    let mut c = session(to);
+    c.select("INBOX").unwrap();
+
+    // then send the e-mail
+    let mut s = smtp(to);
+    let e = lettre_email::Email::builder()
+        .from("sender@localhost")
+        .to(to)
+        .subject("My first e-mail")
+        .text("Hello world from SMTP")
+        .build()
+        .unwrap();
+    s.send(e.into()).unwrap();
+
+    // now we should see the e-mail!
+    let inbox = c.search("ALL").unwrap();
+    // and the one message should have the first message sequence number
+    assert_eq!(inbox.len(), 1);
+    assert!(inbox.contains(&1));
+
+    // we should also get two unsolicited responses: Exists and Recent
+    c.noop().unwrap();
+    let mut unsolicited = Vec::new();
+    while let Ok(m) = c.unsolicited_responses.try_recv() {
+        unsolicited.push(m);
+    }
+    assert_eq!(unsolicited.len(), 2);
+    assert!(unsolicited
+        .iter()
+        .any(|m| m == &imap::types::UnsolicitedResponse::Exists(1)));
+    assert!(unsolicited
+        .iter()
+        .any(|m| m == &imap::types::UnsolicitedResponse::Recent(1)));
+
+    // let's see that we can also fetch the e-mail
+    let fetch = c.fetch("1", "(ALL UID)").unwrap();
+    assert_eq!(fetch.len(), 1);
+    let fetch = &fetch[0];
+    assert_eq!(fetch.message, 1);
+    assert_ne!(fetch.uid, None);
+    assert_eq!(fetch.size, Some(138));
+    let e = fetch.envelope().unwrap();
+    assert_eq!(e.subject, Some("My first e-mail"));
+    assert_ne!(e.from, None);
+    assert_eq!(e.from.as_ref().unwrap().len(), 1);
+    let from = &e.from.as_ref().unwrap()[0];
+    assert_eq!(from.mailbox, Some("sender"));
+    assert_eq!(from.host, Some("localhost"));
+    assert_ne!(e.to, None);
+    assert_eq!(e.to.as_ref().unwrap().len(), 1);
+    let to = &e.to.as_ref().unwrap()[0];
+    assert_eq!(to.mailbox, Some("inbox"));
+    assert_eq!(to.host, Some("localhost"));
+
+    // and let's delete it to clean up
+    c.store("1", "+FLAGS (\\Deleted)").unwrap();
+    c.expunge().unwrap();
+
+    // the e-mail should be gone now
+    // TODO: https://github.com/djc/tokio-imap/issues/34
+    // let inbox = c.search("ALL").unwrap();
+    // assert_eq!(inbox.len(), 0);
+}
+
+#[test]
+fn inbox_uid() {
+    let to = "inbox-uid@localhost";
+
+    // first log in so we'll see the unsolicited e-mails
+    let mut c = session(to);
+    c.select("INBOX").unwrap();
+
+    // then send the e-mail
+    let mut s = smtp(to);
+    let e = lettre_email::Email::builder()
+        .from("sender@localhost")
+        .to(to)
+        .subject("My first e-mail")
+        .text("Hello world from SMTP")
+        .build()
+        .unwrap();
+    s.send(e.into()).unwrap();
+
+    // now we should see the e-mail!
+    let inbox = c.uid_search("ALL").unwrap();
+    // and the one message should have the first message sequence number
+    assert_eq!(inbox.len(), 1);
+    let uid = inbox.into_iter().next().unwrap();
+
+    // we should also get two unsolicited responses: Exists and Recent
+    c.noop().unwrap();
+    let mut unsolicited = Vec::new();
+    while let Ok(m) = c.unsolicited_responses.try_recv() {
+        unsolicited.push(m);
+    }
+    assert_eq!(unsolicited.len(), 2);
+    assert!(unsolicited
+        .iter()
+        .any(|m| m == &imap::types::UnsolicitedResponse::Exists(1)));
+    assert!(unsolicited
+        .iter()
+        .any(|m| m == &imap::types::UnsolicitedResponse::Recent(1)));
+
+    // let's see that we can also fetch the e-mail
+    let fetch = c.uid_fetch(format!("{}", uid), "(ALL UID)").unwrap();
+    assert_eq!(fetch.len(), 1);
+    let fetch = &fetch[0];
+    assert_eq!(fetch.uid, Some(uid));
+    let e = fetch.envelope().unwrap();
+    assert_eq!(e.subject, Some("My first e-mail"));
+
+    // and let's delete it to clean up
+    c.uid_store(format!("{}", uid), "+FLAGS (\\Deleted)")
+        .unwrap();
+    c.expunge().unwrap();
+
+    // the e-mail should be gone now
+    // TODO: https://github.com/djc/tokio-imap/issues/34
+    // let inbox = c.search("ALL").unwrap();
+    // assert_eq!(inbox.len(), 0);
+}
+
+#[test]
+fn list() {
+    let mut s = session("readonly-test@localhost");
+    s.select("INBOX").unwrap();
+    let subdirs = s.list(None, Some("%")).unwrap();
+    assert_eq!(subdirs.len(), 0);
+
+    // TODO: make a subdir
+}