diff --git a/c2rust-transpile/tests/snapshots.rs b/c2rust-transpile/tests/snapshots.rs
index 83c631b0de..a927571f18 100644
--- a/c2rust-transpile/tests/snapshots.rs
+++ b/c2rust-transpile/tests/snapshots.rs
@@ -1,7 +1,6 @@
 use std::env::current_dir;
-use std::ffi::OsString;
 use std::fs;
-use std::path::{Path, PathBuf};
+use std::path::Path;
 use std::process::Command;
 
 use c2rust_transpile::{ReplaceMode, TranspilerConfig};
@@ -59,28 +58,47 @@ fn transpile(platform: Option<&str>, c_path: &Path) {
     c2rust_transpile::transpile(config(), &temp_path, &[]);
     let cwd = current_dir().unwrap();
     let c_path = c_path.strip_prefix(&cwd).unwrap();
+    // The crate name can't have `.`s in it, so use the file stem.
+    // This is also why we set it explicitly with `--crate-name`,
+    // as once we add `.{platform}`, the crate name derived from
+    // the file name won't be valid anymore.
+    let crate_name = c_path.file_stem().unwrap().to_str().unwrap();
     let rs_path = c_path.with_extension("rs");
+    // We need to move the `.rs` file to a platform-specific name
+    // so that they don't overwrite each other.
+    let rs_path = match platform {
+        None => rs_path,
+        Some(platform) => {
+            let platform_rs_path = rs_path.with_extension(format!("{platform}.rs"));
+            fs::rename(&rs_path, &platform_rs_path).unwrap();
+            platform_rs_path
+        }
+    };
     let rs = fs::read_to_string(&rs_path).unwrap();
     let debug_expr = format!("cat {}", rs_path.display());
 
-    let name = platform
-        .map(|platform| ["transpile", platform].join("-"))
-        .unwrap_or("transpile".into());
-
-    insta::assert_snapshot!(name, &rs, &debug_expr);
+    let snapshot_name = match platform {
+        None => "transpile".into(),
+        Some(platform) => format!("transpile-{platform}"),
+    };
+    insta::assert_snapshot!(snapshot_name, &rs, &debug_expr);
 
+    // Don't need to worry about platform clashes here, as this is immediately deleted.
+    let rlib_path = format!("lib{crate_name}.rlib");
     let status = Command::new("rustc")
-        .args(&["--crate-type", "lib", "--edition", "2021"])
+        .args(&[
+            "--crate-type",
+            "lib",
+            "--edition",
+            "2021",
+            "--crate-name",
+            crate_name,
+            "-o",
+            &rlib_path,
+        ])
         .arg(&rs_path)
         .status();
     assert!(status.unwrap().success());
-    let rlib_path = {
-        let mut file_name = OsString::new();
-        file_name.push("lib");
-        file_name.push(rs_path.file_stem().unwrap());
-        file_name.push(".rlib");
-        PathBuf::from(file_name)
-    };
     fs::remove_file(&rlib_path).unwrap();
 }
 
diff --git a/c2rust-transpile/tests/snapshots/platform-specific/dummy.c b/c2rust-transpile/tests/snapshots/platform-specific/dummy.c
deleted file mode 100644
index f658d3bd1e..0000000000
--- a/c2rust-transpile/tests/snapshots/platform-specific/dummy.c
+++ /dev/null
@@ -1,2 +0,0 @@
-/* empty file until we have multiple tests; if we glob only one test, insta
-omits the `@file.c` suffix from snapshots */
diff --git a/c2rust-transpile/tests/snapshots/platform-specific/dummy.rs b/c2rust-transpile/tests/snapshots/platform-specific/dummy.rs
deleted file mode 100644
index d5e9115dc0..0000000000
--- a/c2rust-transpile/tests/snapshots/platform-specific/dummy.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-#![allow(
-    dead_code,
-    mutable_transmutes,
-    non_camel_case_types,
-    non_snake_case,
-    non_upper_case_globals,
-    unused_assignments,
-    unused_mut
-)]
diff --git a/c2rust-transpile/tests/snapshots/platform-specific/rnd.rs b/c2rust-transpile/tests/snapshots/platform-specific/rnd.linux.rs
similarity index 100%
rename from c2rust-transpile/tests/snapshots/platform-specific/rnd.rs
rename to c2rust-transpile/tests/snapshots/platform-specific/rnd.linux.rs
diff --git a/c2rust-transpile/tests/snapshots/platform-specific/rnd.macos.rs b/c2rust-transpile/tests/snapshots/platform-specific/rnd.macos.rs
new file mode 100644
index 0000000000..f8d84fc2d2
--- /dev/null
+++ b/c2rust-transpile/tests/snapshots/platform-specific/rnd.macos.rs
@@ -0,0 +1,29 @@
+#![allow(
+    dead_code,
+    mutable_transmutes,
+    non_camel_case_types,
+    non_snake_case,
+    non_upper_case_globals,
+    unused_assignments,
+    unused_mut
+)]
+extern "C" {
+    fn abs(_: std::ffi::c_int) -> std::ffi::c_int;
+}
+pub type int32_t = std::ffi::c_int;
+pub type uint32_t = std::ffi::c_uint;
+#[no_mangle]
+pub static mut cur_rand_seed: uint32_t = 0 as std::ffi::c_int as uint32_t;
+#[no_mangle]
+pub unsafe extern "C" fn set_rand_seed(mut s: uint32_t) {
+    cur_rand_seed = s;
+}
+#[no_mangle]
+pub unsafe extern "C" fn get_rand_seed() -> uint32_t {
+    let INCREMENT: uint32_t = 1 as std::ffi::c_int as uint32_t;
+    let MULTIPLIER: uint32_t = 0x15a4e35 as std::ffi::c_int as uint32_t;
+    cur_rand_seed = MULTIPLIER.wrapping_mul(cur_rand_seed).wrapping_add(INCREMENT);
+    let mut ret: uint32_t = abs(cur_rand_seed as int32_t) as uint32_t;
+    return ret;
+}
+
diff --git a/c2rust-transpile/tests/snapshots/platform-specific/rotate.rs b/c2rust-transpile/tests/snapshots/platform-specific/rotate.linux.rs
similarity index 100%
rename from c2rust-transpile/tests/snapshots/platform-specific/rotate.rs
rename to c2rust-transpile/tests/snapshots/platform-specific/rotate.linux.rs
diff --git a/c2rust-transpile/tests/snapshots/platform-specific/rotate.macos.rs b/c2rust-transpile/tests/snapshots/platform-specific/rotate.macos.rs
new file mode 100644
index 0000000000..90236c1054
--- /dev/null
+++ b/c2rust-transpile/tests/snapshots/platform-specific/rotate.macos.rs
@@ -0,0 +1,22 @@
+#![allow(
+    dead_code,
+    mutable_transmutes,
+    non_camel_case_types,
+    non_snake_case,
+    non_upper_case_globals,
+    unused_assignments,
+    unused_mut
+)]
+#[no_mangle]
+pub unsafe extern "C" fn rotate_left_64(
+    mut x: std::ffi::c_ulonglong,
+) -> std::ffi::c_ulonglong {
+    return x.rotate_left(4 as std::ffi::c_int as std::ffi::c_ulonglong as u32);
+}
+#[no_mangle]
+pub unsafe extern "C" fn rotate_right_64(
+    mut x: std::ffi::c_ulonglong,
+) -> std::ffi::c_ulonglong {
+    return x.rotate_right(4 as std::ffi::c_int as std::ffi::c_ulonglong as u32);
+}
+
diff --git a/c2rust-transpile/tests/snapshots/snapshots__transpile-linux@dummy.c.snap b/c2rust-transpile/tests/snapshots/snapshots__transpile-linux@dummy.c.snap
deleted file mode 100644
index 99cb238cc0..0000000000
--- a/c2rust-transpile/tests/snapshots/snapshots__transpile-linux@dummy.c.snap
+++ /dev/null
@@ -1,16 +0,0 @@
----
-source: c2rust-transpile/tests/snapshots.rs
-assertion_line: 69
-expression: cat tests/snapshots/platform-specific/dummy.rs
-input_file: c2rust-transpile/tests/snapshots/platform-specific/dummy.c
----
-#![allow(
-    dead_code,
-    mutable_transmutes,
-    non_camel_case_types,
-    non_snake_case,
-    non_upper_case_globals,
-    unused_assignments,
-    unused_mut
-)]
-
diff --git a/c2rust-transpile/tests/snapshots/snapshots__transpile-macos@dummy.c.snap b/c2rust-transpile/tests/snapshots/snapshots__transpile-macos@dummy.c.snap
deleted file mode 100644
index 99cb238cc0..0000000000
--- a/c2rust-transpile/tests/snapshots/snapshots__transpile-macos@dummy.c.snap
+++ /dev/null
@@ -1,16 +0,0 @@
----
-source: c2rust-transpile/tests/snapshots.rs
-assertion_line: 69
-expression: cat tests/snapshots/platform-specific/dummy.rs
-input_file: c2rust-transpile/tests/snapshots/platform-specific/dummy.c
----
-#![allow(
-    dead_code,
-    mutable_transmutes,
-    non_camel_case_types,
-    non_snake_case,
-    non_upper_case_globals,
-    unused_assignments,
-    unused_mut
-)]
-