Cargo test quicker by not building untested examples when filtered

src/bin/cargo/commands/test.rs

@@ -94,6 +94,17 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
 
     let mut compile_opts = args.compile_options(config, CompileMode::Test, Some(&ws))?;
 
+    // `TESTNAME` is actually an argument of the test binary, but it's
+    // important, so we explicitly mention it and reconfigure.
+    let test_name: Option<&str> = args.value_of("TESTNAME");
+    let mut test_args = vec![];
+    test_args.extend(test_name.into_iter().map(|s| s.to_string()));
+    test_args.extend(
+        args.values_of("args")
+            .unwrap_or_default()
+            .map(|s| s.to_string()),
+    );
+
     let no_run = args.is_present("no-run");
     let doc = args.is_present("doc");
     if doc {
@@ -117,6 +128,16 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
             FilterRule::none(),
             FilterRule::none(),
         );
+    } else if test_name.is_some() {
+        if let CompileFilter::Default { .. } = compile_opts.filter {
+            compile_opts.filter = ops::CompileFilter::new(
+                LibRule::Default, // compile the library, so the unit tests can be run filtered
+                FilterRule::All,    // compile the binaries, so the unit tests in binaries can be run filtered
+                FilterRule::All,    // compile the tests, so the integration tests can be run filtered
+                FilterRule::none(), // specify --examples to unit test binaries filtered
+                FilterRule::none(), // specify --benches to unit test benchmarks filtered
+            ); // also, specify --doc to run doc tests filtered
+        }
     }
 
     let ops = ops::TestOptions {
@@ -125,16 +146,6 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         compile_opts,
     };
 
-    // `TESTNAME` is actually an argument of the test binary, but it's
-    // important, so we explicitly mention it and reconfigure.
-    let mut test_args = vec![];
-    test_args.extend(args.value_of("TESTNAME").into_iter().map(|s| s.to_string()));
-    test_args.extend(
-        args.values_of("args")
-            .unwrap_or_default()
-            .map(|s| s.to_string()),
-    );
-
     let err = ops::run_tests(&ws, &ops, &test_args)?;
     match err {
         None => Ok(()),

tests/testsuite/freshness.rs

@@ -247,7 +247,6 @@ fn changing_profiles_caches_targets() {
             "\
 [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
 [RUNNING] target[..]debug[..]deps[..]foo-[..][EXE]
-[DOCTEST] foo
 ",
         )
         .run();

tests/testsuite/test.rs

@@ -163,7 +163,8 @@ fn cargo_test_verbose() {
 [COMPILING] foo v0.5.0 ([CWD])
 [RUNNING] `rustc [..] src/main.rs [..]`
 [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
-[RUNNING] `[..]target/debug/deps/foo-[..][EXE] hello`",
+[RUNNING] `[CWD]/target/debug/deps/foo-[..] hello`
+",
         )
         .with_stdout_contains("test test_hello ... ok")
         .run();
@@ -601,21 +602,21 @@ fn pass_through_command_line() {
 [COMPILING] foo v0.0.1 ([CWD])
 [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
 [RUNNING] target/debug/deps/foo-[..][EXE]
-[DOCTEST] foo",
+",
         )
+        .with_stdout_contains("running 1 test")
         .with_stdout_contains("test bar ... ok")
-        .with_stdout_contains("running 0 tests")
         .run();
 
     p.cargo("test foo")
         .with_stderr(
             "\
 [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
 [RUNNING] target/debug/deps/foo-[..][EXE]
-[DOCTEST] foo",
+",
         )
+        .with_stdout_contains("running 1 test")
         .with_stdout_contains("test foo ... ok")
-        .with_stdout_contains("running 0 tests")
         .run();
 }
 
@@ -1462,6 +1463,37 @@ fn test_run_implicit_example_target() {
         .run();
 }
 
+#[test]
+fn test_filtered_excludes_compiling_examples() {
+    let p = project()
+        .file(
+            "src/lib.rs",
+            "#[cfg(test)] mod tests { #[test] fn foo() { assert!(true); } }",
+        )
+        .file("examples/ex1.rs", "fn main() {}")
+        .build();
+
+    p.cargo("test -v foo")
+        .with_stdout(
+            "
+running 1 test
+test tests::foo ... ok
+
+test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
+
+",
+        )
+        .with_stderr("\
+[COMPILING] foo v0.0.1 ([CWD])
+[RUNNING] `rustc --crate-name foo src/lib.rs [..] --test [..]`
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
+[RUNNING] `[CWD]/target/debug/deps/foo-[..] foo`
+",
+        )
+        .with_stderr_does_not_contain("[RUNNING][..]rustc[..]ex1[..]")
+        .run();
+}
+
 #[test]
 fn test_no_harness() {
     let p = project()