From 44e97306afb0d1a1897d86eabfa70f8e92cc5289 Mon Sep 17 00:00:00 2001
From: Simon Chopin <schopin@mozilla.com>
Date: Fri, 14 Aug 2026 16:19:09 +0200
Subject: [PATCH] tests: get a test on module list properties

We're about to do some extensive work on the module list, and the
existing integration tests only cover the "which modules do we have"
part.

Let's add a new test that encodes some other properties of the list: it
starts with the executable, and the modules don't overlap. This should
make working on that specific feature feel a bit more confident.
---
 tests/linux_minidump_writer.rs | 45 ++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/tests/linux_minidump_writer.rs b/tests/linux_minidump_writer.rs
index 576c3a42..5483f3df 100644
--- a/tests/linux_minidump_writer.rs
+++ b/tests/linux_minidump_writer.rs
@@ -232,6 +232,51 @@ contextual_test! {
     }
 }
 
+/// A module list starts with the executable and doesn't have overlaps
+#[test]
+fn module_list_properties() {
+    let mut child = start_child_and_wait_for_threads(1);
+    let pid = child.id() as i32;
+
+    let executable = std::fs::read_link(format!("/proc/{pid}/exe")).expect("failed to read exe");
+
+    let mut tmpfile = tempfile::Builder::new()
+        .prefix("module_list")
+        .tempfile()
+        .unwrap();
+
+    MinidumpWriterConfig::new(pid, pid)
+        .write(&mut tmpfile)
+        .expect("could not write minidump");
+
+    child.kill().expect("Failed to kill process");
+    child.wait().expect("Failed to wait for child");
+
+    let dump = Minidump::read_path(tmpfile.path()).expect("failed to read minidump");
+    let module_list: MinidumpModuleList = dump
+        .get_stream()
+        .expect("Couldn't find stream MinidumpModuleList");
+    let modules: Vec<_> = module_list.iter().collect();
+    assert!(!modules.is_empty(), "no modules in the dump");
+
+    // Executable is first
+    assert_eq!(modules[0].code_file(), executable.to_string_lossy());
+
+    // Get the ranges ordered by their start
+    let mut ranges: Vec<_> = modules
+        .iter()
+        .map(|module| (module.base_address(), module.size()))
+        .collect();
+    ranges.sort_unstable();
+
+    // Test for overlap
+    for pair in ranges.windows(2) {
+        let (base, size) = pair[0];
+        let (next_base, _) = pair[1];
+        assert!(base + size <= next_base);
+    }
+}
+
 contextual_test! {
     fn write_with_additional_memory(context: Context) {
         let mut child = start_child_and_return(&["spawn_alloc_wait"]);