tests/read/macho: add testing for go Mach-O executables

This commit updates the submodule for the testfiles to include the
Mach-O binaries produced by the Go compiler and then exercises the
logic in the previous commits. The new testfiles commit is due to
gimli-rs/object-testfiles#14.

tests/read/macho.rs

@@ -0,0 +1,49 @@
+#[cfg(feature = "std")]
+use object::{Object, ObjectSection as _};
+
+// Test that we can read compressed sections in Mach-O files as produced
+// by the Go compiler.
+#[cfg(feature = "std")]
+#[test]
+fn test_go_macho() {
+    let macho_testfiles = std::path::Path::new("testfiles/macho");
+
+    // Section names we expect to find, whether they should be
+    // compressed, and the actual name of the section in the file.
+    const EXPECTED: &[(&str, bool, &str)] = &[
+        (".debug_abbrev", true, "__zdebug_abbrev"),
+        (".debug_gdb_scripts", false, "__debug_gdb_scri"),
+        (".debug_ranges", true, "__zdebug_ranges"),
+        ("__data", false, "__data"),
+    ];
+
+    for file in &["go-aarch64", "go-x86_64"] {
+        let path = macho_testfiles.join(file);
+        let file = std::fs::File::open(path).unwrap();
+        let reader = object::read::ReadCache::new(file);
+        let object = object::read::File::parse(&reader).unwrap();
+        for &(name, compressed, actual_name) in EXPECTED {
+            let section = object.section_by_name(name).unwrap();
+            assert_eq!(section.name(), Ok(actual_name));
+            let compressed_file_range = section.compressed_file_range().unwrap();
+            let size = section.size();
+            if compressed {
+                assert_eq!(
+                    compressed_file_range.format,
+                    object::CompressionFormat::Zlib
+                );
+                assert_eq!(compressed_file_range.compressed_size, size - 12);
+                assert!(
+                    compressed_file_range.uncompressed_size > compressed_file_range.compressed_size,
+                    "decompressed size is greater than compressed size"
+                );
+            } else {
+                assert_eq!(
+                    compressed_file_range.format,
+                    object::CompressionFormat::None
+                );
+                assert_eq!(compressed_file_range.compressed_size, size);
+            }
+        }
+    }
+}

tests/read/mod.rs

@@ -2,3 +2,4 @@
 
 mod coff;
 mod elf;
+mod macho;