From f8740b8bd7043b64341be7d40617fcb34005bbee Mon Sep 17 00:00:00 2001
From: elvis <elvilio98@gmail.com>
Date: Fri, 22 Aug 2025 01:40:15 +0200
Subject: [PATCH] Better tests

---
 src/rsprocess/assert/tests.rs |  70 +++---
 src/rsprocess/transitions.rs  | 437 +++++++++++++++++++++-------------
 2 files changed, 311 insertions(+), 196 deletions(-)

diff --git a/src/rsprocess/assert/tests.rs b/src/rsprocess/assert/tests.rs
index 88534f8..ed8f341 100644
--- a/src/rsprocess/assert/tests.rs
+++ b/src/rsprocess/assert/tests.rs
@@ -9,7 +9,7 @@ use super::rsassert::*;
 type LocalAssert = RSassert<EdgeRelablerInput>;
 
 #[test]
-fn assert_tycheck_true() {
+fn return_true() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -29,7 +29,7 @@ fn assert_tycheck_true() {
 }
 
 #[test]
-fn assert_tycheck_concat_1() {
+fn concat_1() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -57,7 +57,7 @@ fn assert_tycheck_concat_1() {
 }
 
 #[test]
-fn assert_tycheck_concat_2() {
+fn concat_2() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -85,7 +85,7 @@ fn assert_tycheck_concat_2() {
 }
 
 #[test]
-fn assert_tycheck_return_1() {
+fn return_1() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -110,7 +110,7 @@ fn assert_tycheck_return_1() {
 }
 
 #[test]
-fn assert_tycheck_return_incompatible_1() {
+fn return_incompatible_1() {
     let tree = LocalAssert {
 	tree: Tree::Concat(
 	    Box::new(Tree::Return(Box::new(Expression::True))),
@@ -121,7 +121,7 @@ fn assert_tycheck_return_incompatible_1() {
 }
 
 #[test]
-fn assert_tycheck_return_incompatible_2() {
+fn return_incompatible_2() {
     let tree = LocalAssert {
 	tree: Tree::Concat(
 	    Box::new(Tree::Return(Box::new(Expression::True))),
@@ -141,7 +141,7 @@ fn assert_tycheck_return_incompatible_2() {
 }
 
 #[test]
-fn assert_tycheck_return_2() {
+fn return_2() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -176,7 +176,7 @@ fn assert_tycheck_return_2() {
 
 
 #[test]
-fn assert_tycheck_return_3() {
+fn return_3() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -210,7 +210,7 @@ fn assert_tycheck_return_3() {
 }
 
 #[test]
-fn assert_tycheck_if_1() {
+fn if_1() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -246,7 +246,7 @@ fn assert_tycheck_if_1() {
 }
 
 #[test]
-fn assert_tycheck_if_2() {
+fn if_2() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -281,7 +281,7 @@ fn assert_tycheck_if_2() {
 }
 
 #[test]
-fn assert_tycheck_if_3() {
+fn if_3() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -317,7 +317,7 @@ fn assert_tycheck_if_3() {
 }
 
 #[test]
-fn assert_tycheck_if_4() {
+fn if_4() {
     let tree = LocalAssert {
 	tree: Tree::Concat(
 	    Box::new(
@@ -339,7 +339,7 @@ fn assert_tycheck_if_4() {
 }
 
 #[test]
-fn assert_tycheck_if_else_1() {
+fn if_else_1() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -378,7 +378,7 @@ fn assert_tycheck_if_else_1() {
 }
 
 #[test]
-fn assert_tycheck_if_else_2() {
+fn if_else_2() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -417,7 +417,7 @@ fn assert_tycheck_if_else_2() {
 }
 
 #[test]
-fn assert_tycheck_if_else_3() {
+fn if_else_3() {
     let tree = LocalAssert {
 	tree: Tree::Concat(
 	    Box::new(
@@ -442,7 +442,7 @@ fn assert_tycheck_if_else_3() {
 }
 
 #[test]
-fn assert_tycheck_if_else_4() {
+fn if_else_4() {
     let tree = LocalAssert {
 	tree: Tree::Concat(
 	    Box::new(
@@ -467,7 +467,7 @@ fn assert_tycheck_if_else_4() {
 }
 
 #[test]
-fn assert_tycheck_assignment_1() {
+fn assignment_1() {
     let tree = LocalAssert {
 	tree: Tree::Assignment(
 	    Variable::Id("a".into()),
@@ -479,7 +479,7 @@ fn assert_tycheck_assignment_1() {
 }
 
 #[test]
-fn assert_tycheck_assignment_2() {
+fn assignment_2() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -516,7 +516,7 @@ fn assert_tycheck_assignment_2() {
 }
 
 #[test]
-fn assert_tycheck_assignment_3() {
+fn assignment_3() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -555,7 +555,7 @@ fn assert_tycheck_assignment_3() {
 }
 
 #[test]
-fn assert_tycheck_assignment_4() {
+fn assignment_4() {
     let tree = LocalAssert {
 	tree: Tree::Concat(
 	    Box::new(
@@ -580,7 +580,7 @@ fn assert_tycheck_assignment_4() {
 }
 
 #[test]
-fn assert_tycheck_assignment_5() {
+fn assignment_5() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -620,7 +620,7 @@ fn assert_tycheck_assignment_5() {
 }
 
 #[test]
-fn assert_tycheck_assignment_6() {
+fn assignment_6() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -667,7 +667,7 @@ fn assert_tycheck_assignment_6() {
 }
 
 #[test]
-fn assert_tycheck_assignment_7() {
+fn assignment_7() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -712,7 +712,7 @@ fn assert_tycheck_assignment_7() {
 }
 
 #[test]
-fn assert_tycheck_assignment_8() {
+fn assignment_8() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -761,7 +761,7 @@ fn assert_tycheck_assignment_8() {
 }
 
 #[test]
-fn assert_tycheck_assignment_9() {
+fn assignment_9() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -808,7 +808,7 @@ fn assert_tycheck_assignment_9() {
 }
 
 #[test]
-fn assert_tycheck_assignment_10() {
+fn assignment_10() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -858,7 +858,7 @@ fn assert_tycheck_assignment_10() {
 
 
 #[test]
-fn assert_tycheck_for_1() {
+fn for_1() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel, RSset};
 
@@ -906,7 +906,7 @@ fn assert_tycheck_for_1() {
 
 
 #[test]
-fn assert_tycheck_for_2() {
+fn for_2() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel, RSset};
 
@@ -958,7 +958,7 @@ fn assert_tycheck_for_2() {
 }
 
 #[test]
-fn assert_tycheck_for_3() {
+fn for_3() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel, RSset};
 
@@ -1024,7 +1024,7 @@ fn assert_tycheck_for_3() {
 }
 
 #[test]
-fn assert_tycheck_for_4() {
+fn for_4() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel, RSset};
 
@@ -1091,7 +1091,7 @@ fn assert_tycheck_for_4() {
 }
 
 #[test]
-fn assert_tycheck_for_5() {
+fn for_5() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel, RSset};
 
@@ -1171,7 +1171,7 @@ fn assert_tycheck_for_5() {
 }
 
 #[test]
-fn assert_tycheck_for_6() {
+fn for_6() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel, RSset};
 
@@ -1262,7 +1262,7 @@ fn assert_tycheck_for_6() {
 }
 
 #[test]
-fn assert_tycheck_for_7() {
+fn for_7() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -1314,7 +1314,7 @@ fn assert_tycheck_for_7() {
 }
 
 #[test]
-fn assert_tycheck_for_8() {
+fn for_8() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel};
 
@@ -1394,7 +1394,7 @@ fn assert_tycheck_for_8() {
 }
 
 #[test]
-fn assert_tycheck_system() {
+fn nodes() {
     use translator::Translator;
     use structure::{RSsystem, RSlabel, RSset, RSenvironment, RSprocess};
     use std::rc::Rc;
diff --git a/src/rsprocess/transitions.rs b/src/rsprocess/transitions.rs
index 2c1c09e..b6d49c0 100644
--- a/src/rsprocess/transitions.rs
+++ b/src/rsprocess/transitions.rs
@@ -1,11 +1,11 @@
 //! Definitions for simple simulation steps.
 
 use super::structure::{RSchoices,
-			   RSenvironment,
-			   RSlabel,
-			   RSprocess,
-			   RSset,
-			   RSsystem};
+		       RSenvironment,
+		       RSlabel,
+		       RSprocess,
+		       RSset,
+		       RSsystem};
 use super::support_structures::TransitionsIterator;
 use std::rc::Rc;
 
@@ -14,216 +14,331 @@ use std::rc::Rc;
 /// of entities and the continuation.
 /// see unfold
 pub fn unfold(
-	environment: &RSenvironment,
-	context_process: &RSprocess,
-	current_entities: &RSset,
+    environment: &RSenvironment,
+    context_process: &RSprocess,
+    current_entities: &RSset,
 ) -> Result<RSchoices, String> {
-	match context_process {
-		RSprocess::Nill => {
-		Ok(RSchoices::new())
+    match context_process {
+	RSprocess::Nill => {
+	    Ok(RSchoices::new())
 	},
-		RSprocess::RecursiveIdentifier { identifier } => {
-			let newprocess = environment.get(*identifier);
-			if let Some(newprocess) = newprocess {
-				unfold(environment, newprocess, current_entities)
-			} else {
-				Err(format!("Missing symbol in context: {identifier}"))
-			}
-		}
-		RSprocess::EntitySet { entities, next_process, } => {
-		Ok(RSchoices::from([(
+	RSprocess::RecursiveIdentifier { identifier } => {
+	    let newprocess = environment.get(*identifier);
+	    if let Some(newprocess) = newprocess {
+		unfold(environment, newprocess, current_entities)
+	    } else {
+		Err(format!("Missing symbol in context: {identifier}"))
+	    }
+	}
+	RSprocess::EntitySet { entities, next_process, } => {
+	    Ok(RSchoices::from([(
 		Rc::new(entities.clone()),
 		Rc::clone(next_process),
-			)]))
+	    )]))
 	},
 	RSprocess::Guarded { reaction, next_process } => {
-		if reaction.enabled(current_entities) {
+	    if reaction.enabled(current_entities) {
 		Ok(RSchoices::from([(Rc::new(reaction.products.clone()),
-					 Rc::clone(next_process))]))
-		} else {
+				     Rc::clone(next_process))]))
+	    } else {
 		Ok(RSchoices::new())
-		}
+	    }
 	}
-		RSprocess::WaitEntity { repeat, repeated_process: _, next_process, }
+	RSprocess::WaitEntity { repeat, repeated_process: _, next_process, }
 	if *repeat <= 0 => {
-		unfold(environment, next_process, current_entities)
+	    unfold(environment, next_process, current_entities)
 	},
-		RSprocess::WaitEntity { repeat, repeated_process, next_process, }
+	RSprocess::WaitEntity { repeat, repeated_process, next_process, }
 	if *repeat == 1 => {
-			let mut choices1 = unfold(environment, repeated_process, current_entities)?;
-			choices1.replace(Rc::clone(next_process));
-			Ok(choices1)
-		}
-		RSprocess::WaitEntity { repeat, repeated_process, next_process, } => {
-			let mut choices1 = unfold(environment, repeated_process, current_entities)?;
-			choices1.replace(Rc::new(RSprocess::WaitEntity {
-				repeat: (*repeat - 1),
-				repeated_process: Rc::clone(repeated_process),
-				next_process: Rc::clone(next_process),
-			}));
-			Ok(choices1)
-		}
-		RSprocess::Summation { children } => {
-			// short-circuits with try_fold.
-			children.iter().try_fold(RSchoices::new(), |mut acc, x| {
-				match unfold(environment, x, current_entities) {
-					Ok(mut choices) => {
-						acc.append(&mut choices);
-						Ok(acc)
-					}
-					Err(e) => Err(e),
-				}
-			})
-		}
-		RSprocess::NondeterministicChoice { children } => {
-			// short-circuits with try_fold.
-			if children.is_empty() {
-				Ok(RSchoices::from(vec![(
-					Rc::new(RSset::new()),
-					Rc::new(RSprocess::Nill),
-				)]))
-			} else {
-				children.iter().try_fold(RSchoices::new(), |mut acc, x| {
-					acc.shuffle(unfold(environment, x, current_entities)?);
-					Ok(acc)
-				})
-			}
-		}
+	    let mut choices1 = unfold(environment,
+				      repeated_process,
+				      current_entities)?;
+	    choices1.replace(Rc::clone(next_process));
+	    Ok(choices1)
 	}
+	RSprocess::WaitEntity { repeat, repeated_process, next_process, } => {
+	    let mut choices1 = unfold(environment,
+				      repeated_process,
+				      current_entities)?;
+	    choices1.replace(Rc::new(RSprocess::WaitEntity {
+		repeat: (*repeat - 1),
+		repeated_process: Rc::clone(repeated_process),
+		next_process: Rc::clone(next_process),
+	    }));
+	    Ok(choices1)
+	}
+	RSprocess::Summation { children } => {
+	    // short-circuits with try_fold.
+	    children.iter().try_fold(RSchoices::new(), |mut acc, x| {
+		match unfold(environment, x, current_entities) {
+		    Ok(mut choices) => {
+			acc.append(&mut choices);
+			Ok(acc)
+		    }
+		    Err(e) => Err(e),
+		}
+	    })
+	}
+	RSprocess::NondeterministicChoice { children } => {
+	    // short-circuits with try_fold.
+	    if children.is_empty() {
+		Ok(RSchoices::from(vec![(
+		    Rc::new(RSset::new()),
+		    Rc::new(RSprocess::Nill),
+		)]))
+	    } else {
+		children.iter().try_fold(RSchoices::new(), |mut acc, x| {
+		    acc.shuffle(unfold(environment, x, current_entities)?);
+		    Ok(acc)
+		})
+	    }
+	}
+    }
 }
 
 pub fn iterator_transitions<'a>(
-	system: &'a RSsystem
+    system: &'a RSsystem
 ) -> Result<TransitionsIterator<'a>, String> {
-	TransitionsIterator::from(system)
+    TransitionsIterator::from(system)
 }
 
 /// see oneTransition, transition, smartTransition, smartOneTransition
 pub fn one_transition(
-	system: &RSsystem
+    system: &RSsystem
 ) -> Result<Option<(RSlabel, RSsystem)>, String> {
-	let mut tr = TransitionsIterator::from(system)?;
-	Ok(tr.next())
+    let mut tr = TransitionsIterator::from(system)?;
+    Ok(tr.next())
 }
 
 /// see allTransitions, smartAllTransitions
 pub fn all_transitions(
-	system: &RSsystem
+    system: &RSsystem
 ) -> Result<Vec<(RSlabel, RSsystem)>, String> {
-	let tr = TransitionsIterator::from(system)?;
-	Ok(tr.collect::<Vec<_>>())
+    let tr = TransitionsIterator::from(system)?;
+    Ok(tr.collect::<Vec<_>>())
 }
 
 /// see oneTarget, smartOneTarget, target, smartTarget
 pub fn target(
-	system: &RSsystem
+    system: &RSsystem
 ) -> Result<(i64, RSset), String> {
-	let current = one_transition(system)?;
-	if current.is_none() {
-		return Ok((0, system.available_entities.clone()));
-	}
-	let mut n = 1;
-	let mut current = current.unwrap().1;
-	while let Some((_, next)) = one_transition(&current)? {
-		current = next;
-		n += 1;
-	}
-	Ok((n, current.available_entities.clone()))
+    let current = one_transition(system)?;
+    if current.is_none() {
+	return Ok((0, system.available_entities.clone()));
+    }
+    let mut n = 1;
+    let mut current = current.unwrap().1;
+    while let Some((_, next)) = one_transition(&current)? {
+	current = next;
+	n += 1;
+    }
+    Ok((n, current.available_entities.clone()))
 }
 
 /// see oneRun, run, smartOneRunEK, smartRunEK
 pub fn run(system: RSsystem) -> Result<Vec<Rc<RSsystem>>, String> {
-	let mut res = vec![Rc::new(system)];
-	while let Some((_, next_sys)) = one_transition(res.last().unwrap())? {
-		res.push(Rc::new(next_sys));
-	}
-	Ok(res)
+    let mut res = vec![Rc::new(system)];
+    while let Some((_, next_sys)) = one_transition(res.last().unwrap())? {
+	res.push(Rc::new(next_sys));
+    }
+    Ok(res)
 }
 
 /// see smartOneRunECT, smartRunECT
 pub fn run_separated(
-	system: &RSsystem
+    system: &RSsystem
 ) -> Result<Vec<(RSset, RSset, RSset)>, String> {
-	let mut res = vec![];
-	let current = one_transition(system)?;
-	if current.is_none() {
-		return Ok(res);
-	}
-	let current = current.unwrap();
-	let (available_entities, context, t) = current.0.get_context();
-	res.push((available_entities.clone(), context.clone(), t.clone()));
-	let mut current = current.1;
-	while let Some((label, next)) = one_transition(&current)? {
-		current = next;
+    let mut res = vec![];
+    let current = one_transition(system)?;
+    if current.is_none() {
+	return Ok(res);
+    }
+    let current = current.unwrap();
+    let (available_entities, context, t) = current.0.get_context();
+    res.push((available_entities.clone(), context.clone(), t.clone()));
+    let mut current = current.1;
+    while let Some((label, next)) = one_transition(&current)? {
+	current = next;
 	let (available_entities, context, t) = label.get_context();
-		res.push((available_entities.clone(), context.clone(), t.clone()));
-	}
-	Ok(res)
+	res.push((available_entities.clone(), context.clone(), t.clone()));
+    }
+    Ok(res)
 }
 
 
 
 fn nth_transition(
-	system: &RSsystem,
-	n: usize,
+    system: &RSsystem,
+    n: usize,
 ) -> Result<Option<(RSlabel, RSsystem)>, String> {
-	let mut tr = TransitionsIterator::from(system)?;
-	Ok(tr.nth(n))
+    let mut tr = TransitionsIterator::from(system)?;
+    Ok(tr.nth(n))
 }
 
 type Trace = Vec<(Option<Rc<RSlabel>>, Rc<RSsystem>)>;
 
 pub fn traces(
-	system: RSsystem,
-	n: usize,
+    system: RSsystem,
+    n: usize,
 ) -> Result<Vec<Trace>, String> {
-	if n == 0 {
-		return Ok(vec![])
+    if n == 0 {
+	return Ok(vec![])
+    }
+    let mut n = n;
+    let mut res : Vec<Trace> = vec![];
+    let mut current_trace: Trace = vec![(None, Rc::new(system))];
+    let mut branch = vec![0];
+    let mut depth = 0;
+    let mut new_branch = true;
+
+    loop {
+	let next_sys = nth_transition(&current_trace[depth].1,
+				      branch[depth])?;
+
+	if let Some((current_label, next_sys)) = next_sys {
+	    depth += 1;
+	    if depth >= branch.len() {
+		branch.push(0);
+		current_trace.push((Some(Rc::new(current_label)),
+				    Rc::new(next_sys)));
+	    } else {
+		branch[depth] = 0;
+		current_trace[depth] = (Some(Rc::new(current_label)),
+					Rc::new(next_sys));
+	    }
+	    new_branch = true;
+	} else {
+	    // at the bottom of a trace, we save to res, then backtrack until
+	    // we find another possible path.
+	    if new_branch {
+		res.push(current_trace[0..depth].to_vec());
+		new_branch = false;
+		n -= 1;
+	    }
+	    if n == 0 {
+		break;
+	    }
+
+	    if depth == 0 {
+		break;
+	    }
+
+	    depth -= 1;
+	    branch[depth] += 1;
 	}
+    }
 
-	let mut n = n;
-	let mut res : Vec<Trace> = vec![];
-	let mut current_trace: Trace = vec![(None, Rc::new(system))];
-	let mut branch = vec![0];
-	let mut depth = 0;
-	let mut new_branch = true;
-
-	loop {
-		let next_sys = nth_transition(&current_trace[depth].1,
-									  branch[depth])?;
-
-		if let Some((current_label, next_sys)) = next_sys {
-			depth += 1;
-			if depth >= branch.len() {
-				branch.push(0);
-				current_trace.push((Some(Rc::new(current_label)),
-									Rc::new(next_sys)));
-			} else {
-				branch[depth] = 0;
-				current_trace[depth] = (Some(Rc::new(current_label)),
-										Rc::new(next_sys));
-			}
-			new_branch = true;
-		} else {
-			// at the bottom of a trace, we save to res, then backtrack until
-			// we find another possible path.
-			if new_branch {
-				res.push(current_trace[0..depth].to_vec());
-				new_branch = false;
-				n -= 1;
-			}
-			if n == 0 {
-				break;
-			}
-
-			if depth == 0 {
-				break;
-			}
-
-			depth -= 1;
-			branch[depth] += 1;
-		}
-	}
-
-	Ok(res)
+    Ok(res)
+}
+
+#[test]
+fn traces_1() {
+    use super::structure::RSreaction;
+
+    let system = RSsystem {
+	delta: Rc::new(RSenvironment::from([
+	    (100, RSprocess::WaitEntity {
+		repeat: 2,
+		repeated_process: Rc::new(RSprocess::EntitySet {
+		    entities: RSset::from([1]),
+		    next_process: Rc::new(RSprocess::Nill)
+		}),
+		next_process: Rc::new(RSprocess::Nill) }),
+	    (102, RSprocess::WaitEntity {
+		repeat: 3,
+		repeated_process: Rc::new(RSprocess::EntitySet {
+		    entities: RSset::from([2]),
+		    next_process: Rc::new(RSprocess::Nill) }),
+		next_process: Rc::new(RSprocess::Nill) }),
+	    (103, RSprocess::WaitEntity {
+		repeat: 4,
+		repeated_process: Rc::new(RSprocess::EntitySet {
+		    entities: RSset::from([3]),
+		    next_process: Rc::new(RSprocess::Nill) }),
+		next_process: Rc::new(RSprocess::Nill) }),
+	    (101, RSprocess::Summation { children: vec![
+		Rc::new(RSprocess::EntitySet {
+		    entities: RSset::from([10]),
+		    next_process: Rc::new(RSprocess::RecursiveIdentifier {
+			identifier: 100 }) }),
+		Rc::new(RSprocess::EntitySet {
+		    entities: RSset::from([11]),
+		    next_process: Rc::new(RSprocess::RecursiveIdentifier {
+			identifier: 102 }) }),
+		Rc::new(RSprocess::EntitySet {
+		    entities: RSset::from([11]),
+		    next_process: Rc::new(RSprocess::RecursiveIdentifier {
+			identifier: 103 }) })
+	    ] }),
+	])),
+	available_entities: RSset::from([1, 2]),
+	context_process: RSprocess::RecursiveIdentifier { identifier: 101 },
+	reaction_rules:
+	Rc::new(vec![RSreaction { reactants: RSset::from([1]),
+				  inhibitors: RSset::from([3]),
+				  products: RSset::from([3]), },
+		     RSreaction { reactants: RSset::from([3]),
+				  inhibitors: RSset::from([1]),
+				  products: RSset::from([1]), },
+		     RSreaction { reactants: RSset::from([2]),
+				  inhibitors: RSset::new(),
+				  products: RSset::from([4]), },
+	])
+    };
+
+    // for (pos, trace) in res.iter().enumerate() {
+    //	println!("trace {}:", pos);
+    //	for (_, sy) in trace {
+    //	    let ent = format!("{:?}", sy.available_entities);
+    //	    let con = format!("{:?}", sy.context_process);
+    //	    println!("\t({}, {})", ent, con);
+    //	}
+    // }
+
+    let res = traces(system.clone(), 1).unwrap();
+    assert_eq!(res.len(), 1);
+
+    let res = traces(system.clone(), 2).unwrap();
+    assert_eq!(res.len(), 2);
+    assert_eq!(res[0].len() + 1, res[1].len());
+
+    let res = traces(system.clone(), 3).unwrap();
+    assert_eq!(res.len(), 3);
+
+    let res = traces(system.clone(), 4).unwrap();
+    assert_eq!(res.len(), 3);
+
+    let res = traces(system.clone(), 0).unwrap();
+    assert_eq!(res.len(), 0);
+}
+
+#[test]
+fn traces_empty_env() {
+    use super::structure::RSreaction;
+
+    let system = RSsystem {
+	delta: Rc::new(RSenvironment::from([])),
+	available_entities: RSset::from([1, 2]),
+	context_process: RSprocess::WaitEntity {
+	    repeat: 10,
+	    repeated_process: Rc::new(RSprocess::EntitySet {
+		entities: RSset::from([1, 2]),
+		next_process: Rc::new(RSprocess::Nill) }),
+	    next_process: Rc::new(RSprocess::Nill) },
+	reaction_rules:
+	Rc::new(vec![RSreaction { reactants: RSset::from([1]),
+				  inhibitors: RSset::from([3]),
+				  products: RSset::from([3]), },
+		     RSreaction { reactants: RSset::from([3]),
+				  inhibitors: RSset::from([1]),
+				  products: RSset::from([1]), },
+		     RSreaction { reactants: RSset::from([2]),
+				  inhibitors: RSset::new(),
+				  products: RSset::from([4]), },
+	])
+    };
+
+    let res = traces(system.clone(), 10).unwrap();
+    assert_eq!(res.len(), 1);
+    assert_eq!(res[0].len(), 10);
 }