Add a clippy test to minicrater

The test runs crater in `clippy` mode and compares `stable` with
`stable+rustflags=-Dclippy::all` so that a regression will appear when
clippy would emit a warning on a crate.

Also adds a new local crate which compiles succesfully but causes clippy
to emit a warning.

Author: ecstatic-morse

local-crates/clippy-warn/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "clippy-warn"
+version = "0.1.0"
+authors = ["Dylan MacKenzie <[email protected]>"]
+edition = "2018"
+
+[dependencies]

local-crates/clippy-warn/src/main.rs

@@ -0,0 +1,4 @@
+fn main() {
+    // Trigger `clippy::print_with_newline`
+    print!("Hello, world!\n");
+}

tests/minicrater/clippy/config.toml

@@ -0,0 +1,25 @@
+[server]
+bot-acl = [
+    "pietroalbini",
+]
+
+[server.labels]
+remove = "^S-"
+experiment-queued = "S-waiting-on-crater"
+experiment-completed = "S-waiting-on-review"
+
+[demo-crates]
+crates = []
+github-repos = []
+local-crates = ["build-pass", "clippy-warn"]
+
+[sandbox]
+memory-limit = "512M"
+build-log-max-size = "2M"
+build-log-max-lines = 1000
+
+[crates]
+
+[github-repos]
+
+[local-crates]

tests/minicrater/clippy/results.expected.json

@@ -0,0 +1,34 @@
+{
+  "crates": [
+    {
+      "name": "build-pass (local)",
+      "res": "test-pass",
+      "runs": [
+        {
+          "log": "stable/local/build-pass",
+          "res": "test-pass"
+        },
+        {
+          "log": "stable%2Brustflags=-Dclippy::all/local/build-pass",
+          "res": "test-pass"
+        }
+      ],
+      "url": "https://github.com/rust-lang-nursery/crater/tree/master/local-crates/build-pass"
+    },
+    {
+      "name": "clippy-warn (local)",
+      "res": "regressed",
+      "runs": [
+        {
+          "log": "stable/local/clippy-warn",
+          "res": "test-pass"
+        },
+        {
+          "log": "stable%2Brustflags=-Dclippy::all/local/clippy-warn",
+          "res": "build-fail:unknown"
+        }
+      ],
+      "url": "https://github.com/rust-lang-nursery/crater/tree/master/local-crates/clippy-warn"
+    }
+  ]
+}

tests/minicrater/driver.rs

@@ -26,6 +26,21 @@ pub(super) struct MinicraterRun {
     pub(super) crate_select: &'static str,
     pub(super) multithread: bool,
     pub(super) ignore_blacklist: bool,
+    pub(super) mode: &'static str,
+    pub(super) toolchains: &'static [&'static str],
+}
+
+impl Default for MinicraterRun {
+    fn default() -> Self {
+        MinicraterRun {
+            ex: "default",
+            crate_select: "demo",
+            multithread: false,
+            ignore_blacklist: false,
+            mode: "build-and-test",
+            toolchains: &["stable", "beta"],
+        }
+    }
 }
 
 impl MinicraterRun {
@@ -54,8 +69,10 @@ impl MinicraterRun {
             .minicrater_exec();
 
         // Define the experiment
+        let mode = format!("--mode={}", self.mode);
         let crate_select = format!("--crate-select={}", self.crate_select);
-        let mut define_args = vec!["define-ex", &ex_arg, "stable", "beta", &crate_select];
+        let mut define_args = vec!["define-ex", &ex_arg, &crate_select, &mode];
+        define_args.extend(self.toolchains);
         if self.ignore_blacklist {
             define_args.push("--ignore-blacklist");
         }

tests/minicrater/mod.rs

@@ -5,35 +5,40 @@ minicrater! {
     single_thread_small {
         ex: "small",
         crate_select: "demo",
-        multithread: false,
-        ignore_blacklist: false,
+        ..Default::default()
     },
 
     single_thread_full {
         ex: "full",
         crate_select: "local",
-        multithread: false,
-        ignore_blacklist: false,
+        ..Default::default()
     },
 
     single_thread_blacklist {
         ex: "blacklist",
         crate_select: "demo",
-        multithread: false,
-        ignore_blacklist: false,
+        ..Default::default()
     },
 
     single_thread_ignore_blacklist {
         ex: "ignore-blacklist",
         crate_select: "demo",
-        multithread: false,
         ignore_blacklist: true,
+        ..Default::default()
     },
 
     multi_thread_full {
         ex: "full",
         crate_select: "local",
         multithread: true,
-        ignore_blacklist: false,
+        ..Default::default()
+    },
+
+    clippy_small {
+        ex: "clippy",
+        crate_select: "demo",
+        mode: "clippy",
+        toolchains: &["stable", "stable+rustflags=-Dclippy::all"],
+        ..Default::default()
     },
 }