Implement CompletedProcess::assert_stdout_contains and improve error output

Author: GuillaumeGomez

src/tools/run-make-support/src/command.rs

@@ -6,7 +6,7 @@ use std::path::Path;
 use std::process::{Command as StdCommand, ExitStatus, Output, Stdio};
 
 use crate::drop_bomb::DropBomb;
-use crate::{assert_not_contains, handle_failed_output};
+use crate::{assert_contains, assert_not_contains, handle_failed_output};
 
 /// This is a custom command wrapper that simplifies working with commands and makes it easier to
 /// ensure that we check the exit status of executed processes.
@@ -167,6 +167,12 @@ impl CompletedProcess {
         self
     }
 
+    #[track_caller]
+    pub fn assert_stdout_contains<S: AsRef<str>>(self, needle: S) -> Self {
+        assert_contains(&self.stdout_utf8(), needle.as_ref());
+        self
+    }
+
     #[track_caller]
     pub fn assert_stdout_not_contains<S: AsRef<str>>(&self, needle: S) -> &Self {
         assert_not_contains(&self.stdout_utf8(), needle.as_ref());
@@ -182,7 +188,7 @@ impl CompletedProcess {
 
     #[track_caller]
     pub fn assert_stderr_contains<S: AsRef<str>>(&self, needle: S) -> &Self {
-        assert!(self.stderr_utf8().contains(needle.as_ref()));
+        assert_contains(&self.stderr_utf8(), needle.as_ref());
         self
     }
 

src/tools/run-make-support/src/lib.rs

@@ -315,6 +315,18 @@ pub fn read_dir<F: Fn(&Path)>(dir: impl AsRef<Path>, callback: F) {
     }
 }
 
+/// Check that `haystack` contains `needle`. Panic otherwise.
+#[track_caller]
+pub fn assert_contains(haystack: &str, needle: &str) {
+    if !haystack.contains(needle) {
+        eprintln!("=== HAYSTACK ===");
+        eprintln!("{}", haystack);
+        eprintln!("=== NEEDLE ===");
+        eprintln!("{}", needle);
+        panic!("needle was not found in haystack");
+    }
+}
+
 /// Check that `haystack` does not contain `needle`. Panic otherwise.
 #[track_caller]
 pub fn assert_not_contains(haystack: &str, needle: &str) {