feat(test): format user code output (#14271)

This commit changes "deno test" to better denote user output coming
from test cases.

This is done by printing "---- output ----" and "---- output end ----"
markers if an output is produced. The output from "console" and
"Deno.core.print" is captured, as well as direct writes to "Deno.stdout"
and "Deno.stderr".

To achieve that new APIs were added to "deno_core" crate, that allow
to replace an existing resource with a different one (while keeping resource
ids intact). Resources for stdout and stderr are replaced by pipes.

Co-authored-by: David Sherret <dsherret@gmail.com>

cli/tools/test.rs

@@ -21,6 +21,7 @@ use crate::graph_util::graph_valid;
 use crate::located_script_name;
 use crate::lockfile;
 use crate::ops;
+use crate::ops::testing::create_stdout_stderr_pipes;
 use crate::proc_state::ProcState;
 use crate::resolver::ImportMapResolver;
 use crate::resolver::JsxResolver;
@@ -80,8 +81,10 @@ pub struct TestDescription {
 #[derive(Debug, Clone, PartialEq, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub enum TestOutput {
-  // TODO(caspervonb): add stdout and stderr redirection.
-  Console(String),
+  PrintStdout(String),
+  PrintStderr(String),
+  Stdout(Vec<u8>),
+  Stderr(Vec<u8>),
 }
 
 #[derive(Debug, Clone, PartialEq, Deserialize)]
@@ -219,8 +222,10 @@ struct PrettyTestReporter {
   concurrent: bool,
   echo_output: bool,
   deferred_step_output: HashMap<TestDescription, Vec<DeferredStepOutput>>,
+  in_test_count: usize,
   last_wait_output_level: usize,
   cwd: Url,
+  did_have_user_output: bool,
 }
 
 impl PrettyTestReporter {
@@ -228,9 +233,11 @@ impl PrettyTestReporter {
     PrettyTestReporter {
       concurrent,
       echo_output,
+      in_test_count: 0,
       deferred_step_output: HashMap::new(),
       last_wait_output_level: 0,
       cwd: Url::from_directory_path(std::env::current_dir().unwrap()).unwrap(),
+      did_have_user_output: false,
     }
   }
 
@@ -251,7 +258,8 @@ impl PrettyTestReporter {
   }
 
   fn force_report_step_wait(&mut self, description: &TestStepDescription) {
-    if self.last_wait_output_level < description.level {
+    let wrote_user_output = self.write_output_end();
+    if !wrote_user_output && self.last_wait_output_level < description.level {
       println!();
     }
     print!("{}{} ...", "  ".repeat(description.level), description.name);
@@ -273,7 +281,8 @@ impl PrettyTestReporter {
       TestStepResult::Failed(_) => colors::red("FAILED").to_string(),
     };
 
-    if self.last_wait_output_level == description.level {
+    let wrote_user_output = self.write_output_end();
+    if !wrote_user_output && self.last_wait_output_level == description.level {
       print!(" ");
     } else {
       print!("{}", "  ".repeat(description.level));
@@ -291,6 +300,16 @@ impl PrettyTestReporter {
       }
     }
   }
+
+  fn write_output_end(&mut self) -> bool {
+    if self.did_have_user_output {
+      println!("{}", colors::gray("----- output end -----"));
+      self.did_have_user_output = false;
+      true
+    } else {
+      false
+    }
+  }
 }
 
 impl TestReporter for PrettyTestReporter {
@@ -311,12 +330,31 @@ impl TestReporter for PrettyTestReporter {
     if !self.concurrent {
       self.force_report_wait(description);
     }
+    self.in_test_count += 1;
   }
 
   fn report_output(&mut self, output: &TestOutput) {
-    if self.echo_output {
-      match output {
-        TestOutput::Console(line) => println!("{}", line),
+    if !self.echo_output {
+      return;
+    }
+
+    if !self.did_have_user_output && self.in_test_count > 0 {
+      self.did_have_user_output = true;
+      println!();
+      println!("{}", colors::gray("------- output -------"));
+    }
+    match output {
+      TestOutput::PrintStdout(line) => {
+        print!("{}", line)
+      }
+      TestOutput::PrintStderr(line) => {
+        eprint!("{}", line)
+      }
+      TestOutput::Stdout(bytes) => {
+        std::io::stdout().write_all(bytes).unwrap();
+      }
+      TestOutput::Stderr(bytes) => {
+        std::io::stderr().write_all(bytes).unwrap();
       }
     }
   }
@@ -327,6 +365,8 @@ impl TestReporter for PrettyTestReporter {
     result: &TestResult,
     elapsed: u64,
   ) {
+    self.in_test_count -= 1;
+
     if self.concurrent {
       self.force_report_wait(description);
 
@@ -351,16 +391,17 @@ impl TestReporter for PrettyTestReporter {
       }
     }
 
+    let wrote_user_output = self.write_output_end();
+    if !wrote_user_output && self.last_wait_output_level == 0 {
+      print!(" ");
+    }
+
     let status = match result {
       TestResult::Ok => colors::green("ok").to_string(),
       TestResult::Ignored => colors::yellow("ignored").to_string(),
       TestResult::Failed(_) => colors::red("FAILED").to_string(),
     };
 
-    if self.last_wait_output_level == 0 {
-      print!(" ");
-    }
-
     println!(
       "{} {}",
       status,
@@ -487,11 +528,17 @@ async fn test_specifier(
   channel: UnboundedSender<TestEvent>,
   options: TestSpecifierOptions,
 ) -> Result<(), AnyError> {
+  let (stdout_writer, stderr_writer) =
+    create_stdout_stderr_pipes(channel.clone());
   let mut worker = create_main_worker(
     &ps,
     specifier.clone(),
     permissions,
-    vec![ops::testing::init(channel.clone())],
+    vec![ops::testing::init(
+      channel.clone(),
+      stdout_writer,
+      stderr_writer,
+    )],
   );
 
   let mut maybe_coverage_collector = if let Some(ref coverage_dir) =