Limit test execution time not to hog CI's computational resources

For `libtest` tests, this utilizes the unstable rustc feature added by
rust-lang/rust#64873 to meter the execution time.

ci/common.yml

@@ -1,5 +1,5 @@
 variables:
-  rustVersion: nightly-2019-10-13
+  rustVersion: nightly-2019-11-11
   linuxPrestep: |
     sudo apt-get update &&
     sudo apt-get install -y \

ci/jobs/cargo-test.yml

@@ -25,6 +25,7 @@ parameters:
   no-default-features: false  # Do not activate the `default` feature
 
   # parameters from libtest `cargo test -- --help`
+  # TODO: specifying a portion of these does not work
   test_flags:
     include-ignored: false      # Run ignored and not ignored tests
     ignored: false              # Run only ignored tests
@@ -41,6 +42,7 @@ parameters:
     quite: false                # Display one character per test instead of one line.
                                 # Alias to --format=terse
     exact: false                # Exactly match filters rather than by substring
+    ensure-time: true           # Treat excess of the test execution time limit as error. (unstable)
     color: ''                   # auto|always|never
                                 # Configure coloring of output: auto = colorize if
                                 # stdout is a tty and tests are run on serially
@@ -50,7 +52,7 @@ parameters:
                                 # Configure formatting of output: pretty = Print verbose
                                 # output; terse = Display one character per test; json =
                                 # Output a json document
-    Z: []                       # unstable-options Enable nightly-only flags: unstable-options = Allow
+    Z: ['unstable-options']     # unstable-options Enable nightly-only flags: unstable-options = Allow
                                 # use of experimental features
 
 
@@ -66,6 +68,11 @@ jobs:
   variables:
     check_flags: ''
     test_build_flags: ''
+
+    # Time limits for `--ensure-time`
+    RUST_TEST_TIME_UNIT: '2,10'
+    RUST_TEST_TIME_INTEGRATION: '4,30'
+    RUST_TEST_TIME_DOCTEST: '8,40'
   steps:
   # Custom pre steps:
   - script: $(prepareScript)
@@ -141,6 +148,10 @@ jobs:
     enabled: ${{ parameters.test_flags['exact'] }}
     displayName: "[cli flag modify]Exactly match filters rather than by substring"
 
+  - script: echo '##vso[task.setvariable variable=check_flags]$(check_flags) --ensure-time'
+    enabled: ${{ parameters.test_flags['ensure-time'] }}
+    displayName: "[cli flag modify]Treat excess of the test execution time limit as error"
+
   - script: echo "##vso[task.setvariable variable=check_flags]$(check_flags) --color ${{ parameters.test_flags['color'] }}"
     enabled: ${{ ne(parameters.test_flags['color'], '') }}
     displayName: "[cli flag modify] Configure coloring of output: ${{ parameters.test_flags['color'] }}"
@@ -150,7 +161,7 @@ jobs:
     displayName: "[cli flag modify] Configure formatting of output: ${{ parameters.test_flags['format'] }}"
 
   - ${{ each z in parameters.test_flags['Z'] }}:
-    - script: echo '##vso[task.setvariableV variable=check_flags]$(check_flags) --Z ${{ z }}'
+    - script: echo '##vso[task.setvariable variable=check_flags]$(check_flags) -Z ${{ z }}'
       displayName: "[cli flag modify] unstable-option: ${{ z }}"
 
   # *********************************************************************************************

tcw3/pal/tests/common/mod.rs

@@ -0,0 +1,9 @@
+use std::time::Duration;
+
+pub fn set_timelimit_default() {
+    std::thread::spawn(|| {
+        std::thread::sleep(Duration::from_secs(30));
+        eprintln!("!!! Time limit exceeed.");
+        std::process::abort();
+    });
+}

tcw3/pal/tests/futures.rs

@@ -2,8 +2,11 @@ use futures::{channel::oneshot::channel, task::LocalSpawnExt};
 use std::{env::var_os, time::Duration};
 use tcw3_pal::{prelude::Wm as _, prelude::*, Wm};
 
+mod common;
+
 fn main() {
     env_logger::init();
+    common::set_timelimit_default();
 
     if let Some(value) = var_os("ST_SKIP_NATIVE_BACKEND_TESTS") {
         if !value.is_empty() && value != "0" {

tcw3/pal/tests/timer.rs

@@ -6,8 +6,11 @@ use std::{
 };
 use tcw3_pal::{prelude::Wm as _, prelude::*, Wm};
 
+mod common;
+
 fn main() {
     env_logger::init();
+    common::set_timelimit_default();
 
     if let Some(value) = var_os("ST_SKIP_NATIVE_BACKEND_TESTS") {
         if !value.is_empty() && value != "0" {