Use proptest's Strategy to generate expressions

1 files changed, 29 insertions, 16 deletions

diff --git a/rust/src/web.rs b/rust/src/web.rs
index 6bc892b..5729083 100644
--- a/rust/src/web.rs
+++ b/rust/src/web.rs
@@ -7,6 +7,7 @@ use futures::try_join;
 use futures::{future::join_all, lock::Mutex};
 use lambda::ast::Value;
 use log::info;
+use proptest::test_runner::TestRunner;
 use rand::rngs::SmallRng;
 use rand::{Rng, SeedableRng};
 use serde::{Deserialize, Serialize};
@@ -38,12 +39,12 @@ enum RegistrationResult {
     UrlAlreadyRegistered { url: String },
 }
 
-#[derive(Debug, PartialEq, Clone)]
+#[derive(Debug, Clone)]
 struct Client {
     id: Uuid,
     url: String,
     grade: u8,
-    rng: SmallRng,
+    runner: TestRunner,
     seed: u64,
 }
 
@@ -59,7 +60,7 @@ impl Client {
     }
 
     fn generate_expr(&mut self) -> (String, String) {
-        let input = generate_expr(self.grade.into(), &mut self.rng);
+        let input = generate_expr(self.grade.into(), &mut self.runner);
         let expected = eval_whnf(&input, &mut Environment::new());
         (input.to_string(), expected.to_string())
     }
@@ -117,7 +118,7 @@ impl AppState for State {
                 url: registration.url.clone(),
                 grade: 1,
                 seed,
-                rng: SmallRng::seed_from_u64(seed),
+                runner: TestRunner::deterministic(),
             }));
             let client_s = client.clone();
             self.clients.insert(registration.url.clone(), client);
@@ -355,15 +356,19 @@ mod app_tests {
         );
     }
 
-    #[test]
-    async fn client_generates_constant_at_level_1() {
-        let mut client = Client {
+    fn client() -> Client {
+        Client {
             id: Uuid::new_v4(),
             url: "http://1.2.3.4".to_string(),
             grade: 1,
             seed: 42,
-            rng: SmallRng::seed_from_u64(42),
-        };
+            runner: TestRunner::deterministic(),
+        }
+    }
+
+    #[test]
+    async fn client_generates_constant_at_level_1() {
+        let mut client = client();
 
         let (input, _) = client.generate_expr();
 
@@ -375,17 +380,25 @@ mod app_tests {
 
     #[test]
     async fn client_generates_different_inputs_on_each_call() {
-        let mut client = Client {
-            id: Uuid::new_v4(),
-            url: "http://1.2.3.4".to_string(),
-            grade: 1,
-            seed: 42,
-            rng: SmallRng::seed_from_u64(42),
-        };
+        let mut client = client();
 
         let (input1, _) = client.generate_expr();
         let (input2, _) = client.generate_expr();
 
         assert_ne!(input1, input2);
     }
+
+    #[test]
+    async fn client_generates_variables_at_level_2() {
+        let mut client = client();
+        client.grade = 2;
+
+        let (input, _) = client.generate_expr();
+
+        let parsed = parse(&input);
+        match parsed[..] {
+            [Value::Sym(_)] => (),
+            _ => panic!("Expected symbol, got {:?}", parsed),
+        }
+    }
 }