de-duplicate code

crates/test-programs/tests/wasm_tests/runtime/mod.rs

@@ -1,2 +1,34 @@
 pub mod cap_std_sync;
 pub mod tokio;
+
+// Configure the test suite environment.
+// Test programs use these environment variables to determine what behavior
+// is expected: different errnos are expected on windows, mac, and other unixes,
+// and other filesystem operations are supported or not.
+pub fn test_suite_environment() -> &'static [(&str, &str)] {
+    #[cfg(windows)]
+    {
+        &[
+            ("ERRNO_MODE_WINDOWS", "1"),
+            // Windows does not support dangling links or symlinks in the filesystem.
+            ("NO_DANGLING_FILESYSTEM", "1"),
+            // Windows does not support fd_allocate.
+            ("NO_FD_ALLOCATE", "1"),
+            // Windows does not support renaming a directory to an empty directory -
+            // empty directory must be deleted.
+            ("NO_RENAME_DIR_TO_EMPTY_DIR", "1"),
+        ]
+    }
+    #[cfg(all(unix, not(target_os = "macos")))]
+    {
+        &[("ERRNO_MODE_UNIX", "1")]
+    }
+    #[cfg(target_os = "macos")]
+    {
+        &[
+            ("ERRNO_MODE_MACOS", "1"),
+            // MacOS does not support fd_allocate
+            ("NO_FD_ALLOCATE", "1"),
+        ]
+    }
+}