1 files changed, 29 insertions, 2 deletions
diff --git a/subplot/benchmark.rs b/subplot/benchmark.rs
index 1a64ecc..7ea4a94 100644
--- a/subplot/benchmark.rs
+++ b/subplot/benchmark.rs
@@ -1,8 +1,10 @@
 // Implementations of Subplot scenario steps for sshca.md.
 
-use subplotlib::steplibrary::runcmd::Runcmd;
-
+use serde_json::value::Value;
+use std::fs::File;
 use std::path::Path;
+use subplotlib::steplibrary::datadir::Datadir;
+use subplotlib::steplibrary::runcmd::Runcmd;
 
 #[derive(Default)]
 struct SubplotContext {}
@@ -24,3 +26,28 @@ fn install_rust_program(context: &ScenarioContext) {
         false,
     )?;
 }
+
+#[step]
+#[context(Datadir)]
+#[context(SubplotContext)]
+fn json_files_match(context: &ScenarioContext, first: &str, second: &str) {
+    context.with(
+        |context: &Datadir| {
+            let first = context.canonicalise_filename(&first).expect("can't use first filename");
+            let first = File::open(&first)?;
+            let first: Value = serde_json::from_reader(&first)?;
+
+            let second = context.canonicalise_filename(&second).expect("can't use second filename");
+            let second = File::open(&second)?;
+            let second: Value = serde_json::from_reader(&second)?;
+
+            if first != second {
+                eprintln!("JSON files differ:\n{:#?}\n\n{:#?}\n", first, second,);
+                panic!("ERROR: JSON files differ");
+            };
+
+            Ok(())
+        },
+        false,
+    );
+}