rpc: add test against fixture from Osmosis (#1328)

The response has been obtained from Osmosis, and has some fields
that e.g. Gaia fixtures did not have non-trivial values for.

rpc/tests/osmosis_fixtures.rs

@@ -0,0 +1,46 @@
+use std::{fs, path::PathBuf};
+
+use tendermint_rpc::{endpoint, Response};
+
+use walkdir::WalkDir;
+
+fn find_fixtures(in_out_folder_name: &str) -> Vec<PathBuf> {
+    WalkDir::new(
+        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("tests")
+            .join("osmosis_fixtures")
+            .join(in_out_folder_name),
+    )
+    .into_iter()
+    .filter_map(|e| e.ok())
+    .filter(|e| {
+        e.file_type().is_file()
+            && e.path().extension().is_some()
+            && e.path().extension().unwrap() == "json"
+    })
+    .map(|e| e.into_path())
+    .collect::<Vec<PathBuf>>()
+}
+
+#[test]
+fn incoming_fixtures() {
+    for json_file in find_fixtures("incoming") {
+        let file_name = json_file
+            .file_name()
+            .unwrap()
+            .to_str()
+            .unwrap()
+            .strip_suffix(".json")
+            .unwrap();
+        let content = fs::read_to_string(&json_file).unwrap();
+        match file_name {
+            "block_results_at_height_10499831" => {
+                let r = endpoint::block_results::v0_34::DialectResponse::from_string(content);
+                assert!(r.is_ok(), "block_results_at_height_10499831: {r:?}");
+            },
+            _ => {
+                panic!("unhandled incoming fixture: {file_name}");
+            },
+        }
+    }
+}