Migrate validate_json.py script to rust in run-make/rustdoc-map-file test

Author: GuillaumeGomez

tests/run-make/rustdoc-map-file/rmake.rs

@@ -1,4 +1,6 @@
-use run_make_support::{python_command, rustdoc};
+use run_make_support::path_helpers::read_dir_entries_recursive;
+use run_make_support::rfs::read_to_string;
+use run_make_support::{jzon, rustdoc};
 
 fn main() {
     let out_dir = "out";
@@ -8,6 +10,48 @@ fn main() {
         .arg("--generate-redirect-map")
         .out_dir(&out_dir)
         .run();
-    // FIXME (GuillaumeGomez): Port the python script to Rust as well.
-    python_command().arg("validate_json.py").arg(&out_dir).run();
+
+    let mut found_file = false;
+    read_dir_entries_recursive(&out_dir, |path| {
+        if !found_file
+            && path.is_file()
+            && path.file_name().map(|name| name == "redirect-map.json").unwrap_or(false)
+        {
+            found_file = true;
+            let generated = read_to_string(path);
+            let expected = read_to_string("expected.json");
+            let generated = jzon::parse(&generated).expect("failed to parse JSON");
+            let expected = jzon::parse(&expected).expect("failed to parse JSON");
+
+            let mut differences = Vec::new();
+            for (key, expected_value) in expected.entries() {
+                match generated.get(key) {
+                    Some(value) => {
+                        if expected_value != value {
+                            differences.push(format!("values for key `{key}` don't match"));
+                        }
+                    }
+                    None => differences.push(format!("missing key `{key}`")),
+                }
+            }
+            for (key, data) in generated.entries() {
+                if !expected.has_key(key) {
+                    differences
+                        .push(format!("Extra data not expected: key: `{key}`, data: `{data}`"));
+                }
+            }
+
+            if !differences.is_empty() {
+                eprintln!("Found differences in JSON files:");
+                for diff in differences {
+                    eprintln!("=> {diff}");
+                }
+                std::process::exit(1);
+            }
+        }
+    });
+
+    if !found_file {
+        panic!("`redirect-map.json` file was not found");
+    }
 }