Auto merge of #33588 - nikomatsakis:compiletest-ui, r=acrichto

add UI testing framework

This adds a framework for capturing and tracking the precise output of rustc, which allows us to check all manner of minor details with the output. It's pretty strict right now -- the output must match almost exactly -- and hence maybe a bit too strict. But I figure we can add wildcards or whatever later. There is also a script intended to make updating the references easy, though the script could make things a *bit* easier (in particular, it'd be nice if it would find the build directory for you automatically).

One thing I was wondering about is the best way to test colors. Since windows doesn't embed those in the output stream, this test framework can't test colors on windows -- so I figure we can just write tests that are ignored on windows and which pass `--color=always` or whatever to rustc.

cc @jonathandturner
r? @alexcrichton

4 files changed, 175 insertions, 1 deletions

diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index ae8beb83530..5ec62e06e37 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -28,6 +28,7 @@ pub enum Mode {
     CodegenUnits,
     Incremental,
     RunMake,
+    Ui,
 }
 
 impl FromStr for Mode {
@@ -47,6 +48,7 @@ impl FromStr for Mode {
           "codegen-units" => Ok(CodegenUnits),
           "incremental" => Ok(Incremental),
           "run-make" => Ok(RunMake),
+          "ui" => Ok(Ui),
           _ => Err(()),
         }
     }
@@ -68,6 +70,7 @@ impl fmt::Display for Mode {
             CodegenUnits => "codegen-units",
             Incremental => "incremental",
             RunMake => "run-make",
+            Ui => "ui",
         }, f)
     }
 }
diff --git a/src/tools/compiletest/src/main.rs b/src/tools/compiletest/src/main.rs
index a9e6c454ffa..cc687b53204 100644
--- a/src/tools/compiletest/src/main.rs
+++ b/src/tools/compiletest/src/main.rs
@@ -50,6 +50,7 @@ pub mod runtest;
 pub mod common;
 pub mod errors;
 mod raise_fd_limit;
+mod uidiff;
 
 fn main() {
     #[cfg(cargobuild)]
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index aa1b9d2bafb..a213c6d2d54 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -11,13 +11,14 @@
 use common::Config;
 use common::{CompileFail, ParseFail, Pretty, RunFail, RunPass, RunPassValgrind};
 use common::{Codegen, DebugInfoLldb, DebugInfoGdb, Rustdoc, CodegenUnits};
-use common::{Incremental, RunMake};
+use common::{Incremental, RunMake, Ui};
 use errors::{self, ErrorKind, Error};
 use json;
 use header::TestProps;
 use header;
 use procsrv;
 use test::TestPaths;
+use uidiff;
 use util::logv;
 
 use std::env;
@@ -29,6 +30,7 @@ use std::io::prelude::*;
 use std::net::TcpStream;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Output, ExitStatus};
+use std::str;
 
 pub fn run(config: Config, testpaths: &TestPaths) {
     match &*config.target {
@@ -118,6 +120,7 @@ impl<'test> TestCx<'test> {
             CodegenUnits => self.run_codegen_units_test(),
             Incremental => self.run_incremental_test(),
             RunMake => self.run_rmake_test(),
+            Ui => self.run_ui_test(),
         }
     }
 
@@ -1314,6 +1317,7 @@ actual:\n\
             Codegen |
             Rustdoc |
             RunMake |
+            Ui |
             CodegenUnits => {
                 // do not use JSON output
             }
@@ -2096,6 +2100,96 @@ actual:\n\
         }
         fs::remove_dir(path)
     }
+
+    fn run_ui_test(&self) {
+        println!("ui: {}", self.testpaths.file.display());
+
+        let proc_res = self.compile_test();
+
+        let expected_stderr_path = self.expected_output_path("stderr");
+        let expected_stderr = self.load_expected_output(&expected_stderr_path);
+
+        let expected_stdout_path = self.expected_output_path("stdout");
+        let expected_stdout = self.load_expected_output(&expected_stdout_path);
+
+        let normalized_stdout = self.normalize_output(&proc_res.stdout);
+        let normalized_stderr = self.normalize_output(&proc_res.stderr);
+
+        let mut errors = 0;
+        errors += self.compare_output("stdout", &normalized_stdout, &expected_stdout);
+        errors += self.compare_output("stderr", &normalized_stderr, &expected_stderr);
+
+        if errors > 0 {
+            println!("To update references, run this command from build directory:");
+            let relative_path_to_file =
+                self.testpaths.relative_dir
+                              .join(self.testpaths.file.file_name().unwrap());
+            println!("{}/update-references.sh '{}' '{}'",
+                     self.config.src_base.display(),
+                     self.config.build_base.display(),
+                     relative_path_to_file.display());
+            self.fatal_proc_rec(&format!("{} errors occurred comparing output.", errors),
+                                &proc_res);
+        }
+    }
+
+    fn normalize_output(&self, output: &str) -> String {
+        let parent_dir = self.testpaths.file.parent().unwrap();
+        let parent_dir_str = parent_dir.display().to_string();
+        output.replace(&parent_dir_str, "$DIR")
+              .replace("\\", "/") // normalize for paths on windows
+              .replace("\r\n", "\n") // normalize for linebreaks on windows
+              .replace("\t", "\\t") // makes tabs visible
+    }
+
+    fn expected_output_path(&self, kind: &str) -> PathBuf {
+        let extension = match self.revision {
+            Some(r) => format!("{}.{}", r, kind),
+            None => kind.to_string(),
+        };
+        self.testpaths.file.with_extension(extension)
+    }
+
+    fn load_expected_output(&self, path: &Path) -> String {
+        if !path.exists() {
+            return String::new();
+        }
+
+        let mut result = String::new();
+        match File::open(path).and_then(|mut f| f.read_to_string(&mut result)) {
+            Ok(_) => result,
+            Err(e) => {
+                self.fatal(&format!("failed to load expected output from `{}`: {}",
+                                    path.display(), e))
+            }
+        }
+    }
+
+    fn compare_output(&self, kind: &str, actual: &str, expected: &str) -> usize {
+        if actual == expected {
+            return 0;
+        }
+
+        println!("normalized {}:\n{}\n", kind, actual);
+        println!("expected {}:\n{}\n", kind, expected);
+        println!("diff of {}:\n", kind);
+        for line in uidiff::diff_lines(actual, expected) {
+            println!("{}", line);
+        }
+
+        let output_file = self.output_base_name().with_extension(kind);
+        match File::create(&output_file).and_then(|mut f| f.write_all(actual.as_bytes())) {
+            Ok(()) => { }
+            Err(e) => {
+                self.fatal(&format!("failed to write {} to `{}`: {}",
+                                    kind, output_file.display(), e))
+            }
+        }
+
+        println!("\nThe actual {0} differed from the expected {0}.", kind);
+        println!("Actual {} saved to {}", kind, output_file.display());
+        1
+    }
 }
 
 struct ProcArgs {
diff --git a/src/tools/compiletest/src/uidiff.rs b/src/tools/compiletest/src/uidiff.rs
new file mode 100644
index 00000000000..66573393971
--- /dev/null
+++ b/src/tools/compiletest/src/uidiff.rs
@@ -0,0 +1,76 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Code for checking whether the output of the compiler matches what is
+//! expected.
+
+pub fn diff_lines(actual: &str, expected: &str) -> Vec<String> {
+    // mega simplistic diff algorithm that just prints the things added/removed
+    zip_all(actual.lines(), expected.lines()).enumerate().filter_map(|(i, (a,e))| {
+        match (a, e) {
+            (Some(a), Some(e)) => {
+                if lines_match(e, a) {
+                    None
+                } else {
+                    Some(format!("{:3} - |{}|\n    + |{}|\n", i, e, a))
+                }
+            },
+            (Some(a), None) => {
+                Some(format!("{:3} -\n    + |{}|\n", i, a))
+            },
+            (None, Some(e)) => {
+                Some(format!("{:3} - |{}|\n    +\n", i, e))
+            },
+            (None, None) => panic!("Cannot get here")
+        }
+    }).collect()
+}
+
+fn lines_match(expected: &str, mut actual: &str) -> bool {
+    for (i, part) in expected.split("[..]").enumerate() {
+        match actual.find(part) {
+            Some(j) => {
+                if i == 0 && j != 0 {
+                    return false
+                }
+                actual = &actual[j + part.len()..];
+            }
+            None => {
+                return false
+            }
+        }
+    }
+    actual.is_empty() || expected.ends_with("[..]")
+}
+
+struct ZipAll<I1: Iterator, I2: Iterator> {
+    first: I1,
+    second: I2,
+}
+
+impl<T, I1: Iterator<Item=T>, I2: Iterator<Item=T>> Iterator for ZipAll<I1, I2> {
+    type Item = (Option<T>, Option<T>);
+    fn next(&mut self) -> Option<(Option<T>, Option<T>)> {
+        let first = self.first.next();
+        let second = self.second.next();
+
+        match (first, second) {
+            (None, None) => None,
+            (a, b) => Some((a, b))
+        }
+    }
+}
+
+fn zip_all<T, I1: Iterator<Item=T>, I2: Iterator<Item=T>>(a: I1, b: I2) -> ZipAll<I1, I2> {
+    ZipAll {
+        first: a,
+        second: b,
+    }
+}