Add expected results to integration test

Results are logs of what we get with old toplevel-based version of lib_machine. These are also congruent with what our tests logged out based on SWI.

Cargo.lock

@@ -2504,7 +2504,9 @@ dependencies = [
  "rustyline",
  "ryu",
  "select",
+ "serde",
  "serde-wasm-bindgen",
+ "serde_json",
  "serial_test",
  "sha3 0.8.2",
  "smallvec",

Cargo.toml

@@ -72,6 +72,9 @@ dashu = "0.4.0"
 num-order = { version = "1.2.0" }
 rand = "0.8.5"
 
+serde_json = "1.0.95"
+serde = "1.0.159"
+
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 libffi = { version = "3.2.0", optional = true }
 hostname = { version = "0.3.1", optional = true }

src/machine/lib_machine.rs

@@ -455,6 +455,7 @@ mod tests {
         let blocks = code.split("=====");
 
         let mut i = 0;
+        let mut last_result: Option<_> = None;
         // Iterate over the blocks
         for block in blocks {
             // Trim the block to remove any leading or trailing whitespace
@@ -471,16 +472,24 @@ mod tests {
                 println!("query #{}: {}", i, query);
                 // Parse and execute the query
                 let result = machine.run_query(query.to_string());
-
-                assert!(result.is_ok());
-
                 // Print the result
                 println!("{:?}", result);
+                assert!(result.is_ok());
+
+                last_result = Some(result);
             } else if let Some(code) = block.strip_prefix("consult") {
                 println!("load code: {}", code);
 
                 // Load the code into the machine
                 machine.consult_module_string("facts", code.to_string());
+            } else if let Some(result) = block.strip_prefix("result") {
+                if let Some(Ok(ref last_result)) = last_result {
+                    assert_eq!(
+                        last_result.to_string().trim(),
+                        result.to_string().trim(),
+                    )
+                }
+                
             }
         }
     }

src/machine/parsed_results.rs

@@ -13,6 +13,79 @@ pub enum QueryResolution {
     Matches(Vec<QueryMatch>),
 }
 
+pub fn prolog_value_to_json_tring(value: Value) -> String {
+    match value {
+        Value::Integer(i) => format!("{}", i),
+        Value::Float(f) => format!("{}", f),
+        Value::Rational(r) => format!("{}", r),
+        Value::Atom(a) => format!("{}", a.as_str()),
+        Value::String(s) => 
+            if let Err(_e) = serde_json::from_str::<serde_json::Value>(s.as_str()) {
+                //treat as string literal
+                //escape double quotes
+                format!("\"{}\"", s
+                    .replace("\"", "\\\"")
+                    .replace("\n", "\\n")
+                    .replace("\t", "\\t")
+                    .replace("\r", "\\r"))
+            } else {
+                //return valid json string
+                s
+            },
+        Value::List(l) => {
+            let mut string_result = "[".to_string();
+            for (i, v) in l.iter().enumerate() {
+                if i > 0 {
+                    string_result.push_str(",");
+                }
+                string_result.push_str(&prolog_value_to_json_tring(v.clone()));
+            }
+            string_result.push_str("]");
+            string_result
+        }
+        Value::Structure(s, l) => {
+            let mut string_result = format!("\"{}\":[", s.as_str());
+            for (i, v) in l.iter().enumerate() {
+                if i > 0 {
+                    string_result.push_str(",");
+                }
+                string_result.push_str(&prolog_value_to_json_tring(v.clone()));
+            }
+            string_result.push_str("]");
+            string_result
+        }
+        _ => "null".to_string(),
+    }
+}
+
+fn prolog_match_to_json_string(query_match: &QueryMatch) -> String {
+    let mut string_result = "{".to_string();
+    for (i, (k, v)) in query_match.bindings.iter().enumerate() {
+        if i > 0 {
+            string_result.push_str(",");
+        }
+        string_result.push_str(&format!("\"{}\":{}", k, prolog_value_to_json_tring(v.clone())));
+    }
+    string_result.push_str("}");
+    string_result
+}
+
+impl ToString for QueryResolution {
+    fn to_string(&self) -> String {
+        match self {
+            QueryResolution::True => "true".to_string(),
+            QueryResolution::False => "false".to_string(),
+            QueryResolution::Matches(matches) => {
+                let matches_json: Vec<String> = matches
+                    .iter()
+                    .map(|m| prolog_match_to_json_string(m))
+                    .collect();
+                format!("[{}]", matches_json.join(","))
+            }
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct QueryMatch {
     pub bindings: BTreeMap<String, Value>,