feat(testing) Testing framework chapter 1, asserts and comments (#342)

* seq_result` -> `seq_ok`; add `seq_err`

`seq_ok` and `seq_err` are consistent with `ok` and `err`, but produce
results sequentially.

* Accept `;;` and longer comments in the sexp parser

Currently they are just dropped, and resulting AIR has different
character positions in the error messages.

* Add "map" assertion

Lookup result in a map by service's first argument.

Cargo.lock

@@ -189,6 +189,7 @@ dependencies = [
  "maplit",
  "nom 7.1.1",
  "nom_locate",
+ "pretty_assertions",
  "serde_json",
  "strum",
 ]

air/tests/test_module/issues/issue_221.rs

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+use air_test_framework::TestExecutor;
 use air_test_utils::prelude::*;
 
 #[test]
@@ -27,24 +28,17 @@ fn issue_221() {
 
     let peer_1_value = "peer_1_value";
     let peer_2_value = "peer_2_value";
-    let mut peer_1 = create_avm(set_variable_call_service(json!(peer_1_value)), peer_1_id);
-    let mut peer_2 = create_avm(set_variable_call_service(json!(peer_2_value)), peer_2_id);
-    let mut join_1 = create_avm(echo_call_service(), join_1_id);
-    let mut set_variable = create_avm(
-        set_variable_call_service(json!([peer_1_id, peer_2_id])),
-        set_variable_id,
-    );
 
     let script = f!(r#"
         (seq
             (seq
                 (seq
                     ;; let's peers be an array of two values [peer_1_id, peer_2_id]
-                    (call "{set_variable_id}" ("" "") [] peers)
+                    (call "{set_variable_id}" ("" "") [] peers) ; ok = ["{peer_1_id}", "{peer_2_id}"]
                     (fold peers peer
                         (par
                             (seq
-                                (call peer ("" "") [] value)
+                                (call peer ("" "") [peer] value) ; map = {{"{peer_1_id}": "{peer_1_value}", "{peer_2_id}": "{peer_2_value}"}}
                                 ;; it's crucial to reproduce this bug to add value to stream
                                 ;; with help of ap instruction
                                 (ap value $stream)
@@ -61,8 +55,8 @@ fn issue_221() {
                     ;; appropriate way and state for (1) is returned
                     (par
                         (par
-                            (call "{join_1_id}" ("" "") [iterator])
-                            (call "{join_2_id}" ("" "") [iterator])
+                            (call "{join_1_id}" ("" "") [iterator]) ; behaviour = echo
+                            (call "{join_2_id}" ("" "") [iterator]) ; behaviour = echo
                         )
                         (next iterator)
                     )
@@ -72,18 +66,20 @@ fn issue_221() {
         )
     "#);
 
-    let result = checked_call_vm!(set_variable, <_>::default(), &script, "", "");
-    let peer_1_result = checked_call_vm!(peer_1, <_>::default(), &script, "", result.data.clone());
-    let peer_2_result = checked_call_vm!(peer_2, <_>::default(), &script, "", result.data.clone());
-
-    let join_1_result = checked_call_vm!(join_1, <_>::default(), &script, "", peer_1_result.data.clone());
-    let join_1_result = checked_call_vm!(
-        join_1,
-        <_>::default(),
+    let executor = TestExecutor::new(
+        TestRunParameters::from_init_peer_id("set_variable_id"),
+        vec![],
+        vec![peer_1_id, peer_2_id].into_iter().map(Into::into),
         &script,
-        join_1_result.data,
-        peer_2_result.data.clone()
-    ); // before 0.20.9 it fails here
+    )
+    .expect("Invalid annotated AIR script");
+
+    let _result = executor.execute_one(set_variable_id).unwrap();
+    let _peer_1_result = executor.execute_one(peer_1_id).unwrap();
+    let _peer_2_result = executor.execute_one(peer_2_id).unwrap();
+
+    let _join_1_result = executor.execute_one(join_1_id).unwrap();
+    let join_1_result = executor.execute_one(join_1_id).unwrap(); // before 0.20.9 it fails here
     let actual_trace = trace_from_result(&join_1_result);
     let expected_trace = vec![
         executed_state::scalar(json!([peer_1_id, peer_2_id])),

crates/testing-framework/Cargo.toml

@@ -24,5 +24,7 @@ serde_json = "1.0.85"
 
 [dev-dependencies]
 maplit = "1.0.2"
+pretty_assertions = "0.6.1"
+
 # We do not want to depend on wasm binary path
 air-test-utils = { path = "../air-lib/test-utils", features = ["test_with_native_code"] }

crates/testing-framework/src/asserts/mod.rs

@@ -36,11 +36,14 @@ pub enum ServiceDefinition {
     Error(CallServiceResult),
     /// Service that may return a new value on subsequent call.  Its keys are either
     /// call number string starting from "0", or "default".
-    // TODO We need to return error results too, so we need to define a call result
-    // for default and individual errors.
-    #[strum_discriminants(strum(serialize = "seq_result"))]
-    SeqResult(HashMap<String, JValue>),
+    #[strum_discriminants(strum(serialize = "seq_ok"))]
+    SeqOk(HashMap<String, JValue>),
+    #[strum_discriminants(strum(serialize = "seq_error"))]
+    SeqError(HashMap<String, CallServiceResult>),
     /// Some known service by name: "echo", "unit" (more to follow).
     #[strum_discriminants(strum(serialize = "behaviour"))]
     Behaviour(String),
+    /// Maps first argument to a value
+    #[strum_discriminants(strum(serialize = "map"))]
+    Map(HashMap<String, JValue>),
 }

crates/testing-framework/src/asserts/parser.rs

@@ -16,9 +16,10 @@
 
 use super::{ServiceDefinition, ServiceTagName};
 use crate::services::JValue;
+use crate::transform::parser::delim_ws;
 
 use air_test_utils::CallServiceResult;
-use nom::{error::VerboseError, IResult, InputTakeAtPosition, Parser};
+use nom::{error::VerboseError, IResult};
 
 use std::{collections::HashMap, str::FromStr};
 
@@ -50,8 +51,10 @@ pub fn parse_kw(inp: &str) -> IResult<&str, ServiceDefinition, ParseError> {
             alt((
                 tag(ServiceTagName::Ok.as_ref()),
                 tag(ServiceTagName::Error.as_ref()),
-                tag(ServiceTagName::SeqResult.as_ref()),
+                tag(ServiceTagName::SeqOk.as_ref()),
+                tag(ServiceTagName::SeqError.as_ref()),
                 tag(ServiceTagName::Behaviour.as_ref()),
+                tag(ServiceTagName::Map.as_ref()),
             )),
             equal(),
             cut(context(
@@ -68,33 +71,26 @@ pub fn parse_kw(inp: &str) -> IResult<&str, ServiceDefinition, ParseError> {
                 Ok(ServiceTagName::Error) => {
                     serde_json::from_str::<CallServiceResult>(value).map(ServiceDefinition::Error)
                 }
-                Ok(ServiceTagName::SeqResult) => {
-                    serde_json::from_str::<HashMap<String, JValue>>(value)
-                        .map(ServiceDefinition::SeqResult)
+                Ok(ServiceTagName::SeqOk) => {
+                    serde_json::from_str(value).map(ServiceDefinition::SeqOk)
+                }
+                Ok(ServiceTagName::SeqError) => {
+                    serde_json::from_str::<HashMap<String, CallServiceResult>>(value)
+                        .map(ServiceDefinition::SeqError)
                 }
                 Ok(ServiceTagName::Behaviour) => Ok(ServiceDefinition::Behaviour(value.to_owned())),
+                Ok(ServiceTagName::Map) => serde_json::from_str(value).map(ServiceDefinition::Map),
                 Err(_) => unreachable!("unknown tag {:?}", tag),
             }
         },
     ))(inp)
 }
 
-pub(crate) fn delim_ws<I, O, E, F>(f: F) -> impl FnMut(I) -> IResult<I, O, E>
-where
-    F: Parser<I, O, E>,
-    E: nom::error::ParseError<I>,
-    I: InputTakeAtPosition,
-    <I as InputTakeAtPosition>::Item: nom::AsChar + Clone,
-{
-    use nom::character::complete::multispace0;
-    use nom::sequence::delimited;
-
-    delimited(multispace0, f, multispace0)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
+    use pretty_assertions::assert_eq;
+    use serde_json::json;
 
     #[test]
     fn test_parse_empty() {
@@ -151,13 +147,13 @@ mod tests {
     }
 
     #[test]
-    fn test_seq_result() {
+    fn test_seq_ok() {
         use serde_json::json;
 
-        let res = ServiceDefinition::from_str(r#"seq_result={"default": 42, "1": true, "3": []}"#);
+        let res = ServiceDefinition::from_str(r#"seq_ok={"default": 42, "1": true, "3": []}"#);
         assert_eq!(
             res,
-            Ok(ServiceDefinition::SeqResult(maplit::hashmap! {
+            Ok(ServiceDefinition::SeqOk(maplit::hashmap! {
                 "default".to_owned() => json!(42),
                 "1".to_owned() => json!(true),
                 "3".to_owned() => json!([]),
@@ -166,15 +162,45 @@ mod tests {
     }
 
     #[test]
-    fn test_seq_result_malformed() {
-        let res = ServiceDefinition::from_str(r#"seq_result={"default": 42, "1": true, "3": ]}"#);
+    fn test_seq_ok_malformed() {
+        let res = ServiceDefinition::from_str(r#"seq_ok={"default": 42, "1": true, "3": ]}"#);
         assert!(res.is_err());
     }
 
     #[test]
-    fn test_seq_result_invalid() {
+    fn test_seq_ok_invalid() {
         // TODO perhaps, we should support both arrays and maps
-        let res = ServiceDefinition::from_str(r#"seq_result=[42, 43]"#);
+        let res = ServiceDefinition::from_str(r#"seq_ok=[42, 43]"#);
+        assert!(res.is_err());
+    }
+
+    #[test]
+    fn test_seq_error() {
+        use serde_json::json;
+
+        let res = ServiceDefinition::from_str(
+            r#"seq_error={"default": {"ret_code": 0, "result": 42}, "1": {"ret_code": 0, "result": true}, "3": {"ret_code": 1, "result": "error"}}"#,
+        );
+        assert_eq!(
+            res,
+            Ok(ServiceDefinition::SeqError(maplit::hashmap! {
+                "default".to_owned() => CallServiceResult::ok(json!(42)),
+                "1".to_owned() => CallServiceResult::ok(json!(true)),
+                "3".to_owned() => CallServiceResult::err(1, json!("error")),
+            })),
+        );
+    }
+
+    #[test]
+    fn test_seq_error_malformed() {
+        let res = ServiceDefinition::from_str(r#"seq_error={"default": 42, "1": true]}"#);
+        assert!(res.is_err());
+    }
+
+    #[test]
+    fn test_seq_error_invalid() {
+        // TODO perhaps, we should support both arrays and maps
+        let res = ServiceDefinition::from_str(r#"seq_error=[42, 43]"#);
         assert!(res.is_err());
     }
 
@@ -183,4 +209,16 @@ mod tests {
         let res = ServiceDefinition::from_str(r#"behaviour=echo"#);
         assert_eq!(res, Ok(ServiceDefinition::Behaviour("echo".to_owned())),);
     }
+
+    #[test]
+    fn test_map() {
+        let res = ServiceDefinition::from_str(r#"map = {"42": [], "a": 2}"#);
+        assert_eq!(
+            res,
+            Ok(ServiceDefinition::Map(maplit::hashmap! {
+                "42".to_owned() => json!([]),
+                "a".to_owned() => json!(2)
+            }))
+        );
+    }
 }

crates/testing-framework/src/execution/mod.rs

@@ -145,10 +145,13 @@ fn build_peers(
 
 #[cfg(test)]
 mod tests {
-    use air_test_utils::prelude::*;
-
     use super::*;
 
+    use air_test_utils::prelude::*;
+    use pretty_assertions::assert_eq;
+
+    use std::ops::Deref;
+
     #[test]
     fn test_execution() {
         let exec = TestExecutor::new(
@@ -248,7 +251,7 @@ mod tests {
     }
 
     #[test]
-    fn test_seq_result() {
+    fn test_seq_ok() {
         let exec = TestExecutor::new(
             TestRunParameters::from_init_peer_id("init_peer_id"),
             vec![],
@@ -260,7 +263,7 @@ mod tests {
       (ap 1 k)
       (fold var i
         (seq
-          (call i.$.p ("service" "func") [i k] k)  ; seq_result = {"0":12,"default":42}
+          (call i.$.p ("service" "func") [i k] k)  ; seq_ok = {"0":12,"default":42}
           (next i)))))
   (call "init_peer_id" ("a" "b") []) ; ok = 0
 )"#,
@@ -322,6 +325,152 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_map() {
+        let exec = TestExecutor::new(
+            TestRunParameters::from_init_peer_id("peer1"),
+            vec![],
+            IntoIterator::into_iter(["peer2", "peer3"]).map(Into::into),
+            r#"
+(seq
+  (call "peer1" ("" "") [] peers) ; ok = ["peer2", "peer3"]
+  (fold peers p
+    (seq
+      (call p ("" "") [p]) ; map = {"peer2": 42, "peer3": 43}
+      (next p)
+)))
+"#,
+        )
+        .unwrap();
+
+        let result_init: Vec<_> = exec.execution_iter("peer1").unwrap().collect();
+
+        assert_eq!(result_init.len(), 1);
+        let outcome1 = &result_init[0];
+        assert_eq!(outcome1.ret_code, 0);
+        assert_eq!(outcome1.error_message, "");
+        assert_next_pks!(&outcome1.next_peer_pks, ["peer2"]);
+
+        {
+            let results2 = exec.execute_all("peer2").unwrap();
+            assert_eq!(results2.len(), 1);
+            let outcome2 = &results2[0];
+            assert_eq!(outcome2.ret_code, 0, "{:?}", outcome2);
+            assert!(exec.execution_iter("peer2").unwrap().next().is_none());
+            assert_next_pks!(&outcome2.next_peer_pks, ["peer3"]);
+        }
+
+        {
+            let results3 = exec.execute_all("peer3").unwrap();
+            assert_eq!(results3.len(), 1);
+            let outcome3 = &results3[0];
+            assert_eq!(outcome3.ret_code, 0, "{:?}", outcome3);
+            assert_next_pks!(&outcome3.next_peer_pks, []);
+
+            let trace = trace_from_result(outcome3);
+
+            assert_eq!(
+                trace.deref(),
+                vec![
+                    executed_state::scalar(json!(["peer2", "peer3"])),
+                    executed_state::scalar(json!(42)),
+                    executed_state::scalar(json!(43)),
+                ]
+            );
+        }
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_map_no_arg() {
+        let exec = TestExecutor::new(
+            TestRunParameters::from_init_peer_id("peer1"),
+            vec![],
+            IntoIterator::into_iter(["peer2", "peer3"]).map(Into::into),
+            r#"
+(call "peer1" ("" "") [] p) ; map = {"any": "key"}
+"#,
+        )
+        .unwrap();
+        let _result_init: Vec<_> = exec.execution_iter("peer1").unwrap().collect();
+    }
+
+    #[test]
+    fn test_seq_error() {
+        let exec = TestExecutor::new(
+            TestRunParameters::from_init_peer_id("init_peer_id"),
+            vec![],
+            IntoIterator::into_iter(["peer2", "peer3"]).map(Into::into),
+            r#"(seq
+  (seq
+    (call "peer1" ("service" "func") [] var)  ; ok = [{"p":"peer2","v":2},{"p":"peer3","v":3}, {"p":"peer4"}]
+    (seq
+      (ap 1 k)
+      (fold var i
+        (seq
+          (call i.$.p ("service" "func") [i.$.v k] k)  ; seq_error = {"0":{"ret_code":0,"result":12},"default":{"ret_code":1,"result":42}}
+          (next i)))))
+  (call "init_peer_id" ("a" "b") []) ; ok = 0
+)"#,
+        )
+        .unwrap();
+
+        let result_init: Vec<_> = exec.execution_iter("init_peer_id").unwrap().collect();
+
+        assert_eq!(result_init.len(), 1);
+        let outcome1 = &result_init[0];
+        assert_eq!(outcome1.ret_code, 0);
+        assert_eq!(outcome1.error_message, "");
+
+        assert!(exec.execution_iter("peer2").unwrap().next().is_none());
+        {
+            let results1 = exec.execute_all("peer1").unwrap();
+            assert_eq!(results1.len(), 1);
+            let outcome1 = &results1[0];
+            assert_eq!(outcome1.ret_code, 0, "{:?}", outcome1);
+            assert!(exec.execution_iter("peer1").unwrap().next().is_none());
+            assert_next_pks!(&outcome1.next_peer_pks, ["peer2"]);
+        }
+
+        {
+            let results2: Vec<_> = exec.execute_all("peer2").unwrap();
+            assert_eq!(results2.len(), 1);
+            let outcome2 = &results2[0];
+            assert_eq!(outcome2.ret_code, 0, "{:?}", outcome2);
+            assert!(exec.execution_iter("peer2").unwrap().next().is_none());
+            assert_next_pks!(&outcome2.next_peer_pks, ["peer3"]);
+
+            let trace = trace_from_result(outcome2);
+            assert_eq!(
+                trace,
+                ExecutionTrace::from(vec![
+                    scalar(json!([{"p":"peer2","v":2},{"p":"peer3","v":3},{"p":"peer4"}])),
+                    scalar_number(12),
+                    request_sent_by("peer2"),
+                ])
+            );
+        }
+
+        {
+            let results3: Vec<_> = exec.execute_all("peer3").unwrap();
+            assert_eq!(results3.len(), 1);
+            // TODO why doesn't it fail?
+            let outcome3 = &results3[0];
+            assert_eq!(outcome3.ret_code, 0, "{:?}", outcome3);
+            assert!(exec.execution_iter("peer3").unwrap().next().is_none());
+
+            let trace = trace_from_result(outcome3);
+            assert_eq!(
+                trace,
+                ExecutionTrace::from(vec![
+                    scalar(json!([{"p":"peer2","v":2},{"p":"peer3","v":3},{"p":"peer4"}])),
+                    scalar_number(12),
+                    request_sent_by("peer2"),
+                ])
+            );
+        }
+    }
+
     #[test]
     fn test_echo() {
         let exec = TestExecutor::new(

crates/testing-framework/src/services/results.rs

@@ -21,8 +21,9 @@ use air_test_utils::{
     prelude::{echo_call_service, unit_call_service},
     CallRequestParams, CallServiceClosure, CallServiceResult,
 };
+use serde_json::json;
 
-use std::{cell::Cell, collections::HashMap, convert::TryInto, time::Duration};
+use std::{borrow::Cow, cell::Cell, collections::HashMap, convert::TryInto, time::Duration};
 
 pub struct ResultService {
     results: HashMap<u32, CallServiceClosure>,
@@ -37,8 +38,10 @@ impl TryInto<CallServiceClosure> for ServiceDefinition {
                 Ok(Box::new(move |_| CallServiceResult::ok(jvalue.clone())))
             }
             ServiceDefinition::Error(call_result) => Ok(Box::new(move |_| call_result.clone())),
-            ServiceDefinition::SeqResult(call_map) => Ok(seq_result_closure(call_map)),
+            ServiceDefinition::SeqOk(call_map) => Ok(seq_ok_closure(call_map)),
+            ServiceDefinition::SeqError(call_map) => Ok(seq_error_closure(call_map)),
             ServiceDefinition::Behaviour(name) => named_service_closure(name),
+            ServiceDefinition::Map(map) => Ok(map_service_closure(map)),
         }
     }
 }
@@ -51,7 +54,7 @@ fn named_service_closure(name: String) -> Result<CallServiceClosure, String> {
     }
 }
 
-fn seq_result_closure(call_map: HashMap<String, serde_json::Value>) -> CallServiceClosure {
+fn seq_ok_closure(call_map: HashMap<String, serde_json::Value>) -> CallServiceClosure {
     let call_number_seq = Cell::new(0);
 
     Box::new(move |_| {
@@ -74,6 +77,45 @@ fn seq_result_closure(call_map: HashMap<String, serde_json::Value>) -> CallServi
     })
 }
 
+fn seq_error_closure(call_map: HashMap<String, CallServiceResult>) -> CallServiceClosure {
+    let call_number_seq = Cell::new(0);
+
+    Box::new(move |_| {
+        let call_number = call_number_seq.get();
+        let call_num_str = call_number.to_string();
+        call_number_seq.set(call_number + 1);
+
+        call_map
+            .get(&call_num_str)
+            .or_else(|| call_map.get("default"))
+            .unwrap_or_else(|| {
+                panic!(
+                    "neither value {} nor default value not found in the {:?}",
+                    call_num_str, call_map
+                )
+            })
+            .clone()
+    })
+}
+
+fn map_service_closure(map: HashMap<String, serde_json::Value>) -> CallServiceClosure {
+    Box::new(move |args| {
+        let key = args
+            .arguments
+            .get(0)
+            .expect("At least one arugment expected");
+        // Strings are looked up by value, other objects -- by string representation.
+        //
+        // For example, `"key"` is looked up as `"key"`, `5` is looked up as `"5"`, `["test"]` is looked up
+        // as `"[\"test\"]"`.
+        let key_repr = match key {
+            serde_json::Value::String(s) => Cow::Borrowed(s.as_str()),
+            val => Cow::Owned(val.to_string()),
+        };
+        CallServiceResult::ok(json!(map.get(key_repr.as_ref()).cloned()))
+    })
+}
+
 impl ResultService {
     pub(crate) fn new(results: HashMap<u32, ServiceDefinition>) -> Result<Self, String> {
         Ok(Self {

crates/testing-framework/src/transform/mod.rs

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-mod parser;
+pub(crate) mod parser;
 pub(crate) mod walker;
 
 use crate::asserts::ServiceDefinition;

crates/testing-framework/src/transform/parser.rs

@@ -15,16 +15,16 @@
  */
 
 use super::{Call, Sexp, Triplet};
-use crate::asserts::{parser::delim_ws, ServiceDefinition};
+use crate::asserts::ServiceDefinition;
 
 use nom::branch::alt;
 use nom::bytes::complete::{is_not, tag};
 use nom::character::complete::{alphanumeric1, multispace0, multispace1, one_of, space1};
 use nom::combinator::{cut, map, map_res, opt, recognize, value};
 use nom::error::{context, VerboseError, VerboseErrorKind};
-use nom::multi::{many1_count, separated_list0};
+use nom::multi::{many0, many1, many1_count, separated_list0};
 use nom::sequence::{delimited, pair, preceded, separated_pair, terminated};
-use nom::IResult;
+use nom::{IResult, InputTakeAtPosition};
 use nom_locate::LocatedSpan;
 
 use std::str::FromStr;
@@ -87,11 +87,11 @@ fn parse_sexp_list(inp: Input<'_>) -> IResult<Input<'_>, Sexp, ParseError<'_>> {
     context(
         "within generic list",
         preceded(
-            terminated(tag("("), multispace0),
+            terminated(tag("("), sexp_multispace0),
             cut(terminated(
-                map(separated_list0(multispace1, parse_sexp), Sexp::list),
+                map(separated_list0(sexp_multispace1, parse_sexp), Sexp::list),
                 preceded(
-                    multispace0,
+                    sexp_multispace0,
                     context("closing parentheses not found", tag(")")),
                 ),
             )),
@@ -150,12 +150,12 @@ fn parse_sexp_call_content(inp: Input<'_>) -> IResult<Input<'_>, Sexp, ParseErro
             // possible variable, closing ")", possible annotation
             pair(
                 terminated(
-                    opt(preceded(multispace1, map(parse_sexp_symbol, Box::new))),
-                    preceded(multispace0, tag(")")),
+                    opt(preceded(sexp_multispace1, map(parse_sexp_symbol, Box::new))),
+                    preceded(sexp_multispace0, tag(")")),
                 ),
                 alt((
                     opt(preceded(pair(space1, tag("; ")), parse_annotation)),
-                    value(None, multispace0),
+                    value(None, sexp_multispace0),
                 )),
             ),
         ),
@@ -183,12 +183,12 @@ fn parse_sexp_call_triplet(inp: Input<'_>) -> IResult<Input<'_>, Box<Triplet>, P
     map(
         separated_pair(
             context("triplet peer_id", parse_sexp),
-            multispace0,
+            sexp_multispace0,
             delimited(
                 delim_ws(tag("(")),
                 separated_pair(
                     context("triplet service name", parse_sexp_string),
-                    multispace0,
+                    sexp_multispace0,
                     context("triplet function name", parse_sexp),
                 ),
                 delim_ws(tag(")")),
@@ -202,13 +202,124 @@ fn parse_sexp_call_arguments(inp: Input<'_>) -> IResult<Input<'_>, Vec<Sexp>, Pa
     delimited(tag("["), separated_list0(multispace1, parse_sexp), tag("]"))(inp)
 }
 
+pub(crate) fn delim_ws<I, O, E, F>(f: F) -> impl FnMut(I) -> IResult<I, O, E>
+where
+    F: nom::Parser<I, O, E>,
+    E: nom::error::ParseError<I>,
+    I: nom::InputTakeAtPosition
+        + nom::InputLength
+        + for<'a> nom::Compare<&'a str>
+        + nom::InputTake
+        + Clone,
+    <I as InputTakeAtPosition>::Item: nom::AsChar + Clone,
+    for<'a> &'a str: nom::FindToken<<I as InputTakeAtPosition>::Item>,
+{
+    delimited(sexp_multispace0, f, sexp_multispace0)
+}
+
+pub(crate) fn sexp_multispace0<I, E>(inp: I) -> IResult<I, (), E>
+where
+    E: nom::error::ParseError<I>,
+    I: InputTakeAtPosition
+        + nom::InputLength
+        + for<'a> nom::Compare<&'a str>
+        + nom::InputTake
+        + Clone,
+    <I as InputTakeAtPosition>::Item: nom::AsChar + Clone,
+    for<'a> &'a str: nom::FindToken<<I as InputTakeAtPosition>::Item>,
+{
+    map(
+        opt(many0(pair(
+            // white space
+            multispace1,
+            // possible ;;, ;;; comment
+            opt(pair(tag(";;"), is_not("\r\n"))),
+        ))),
+        |_| (),
+    )(inp)
+}
+
+pub(crate) fn sexp_multispace1(inp: Input<'_>) -> IResult<Input<'_>, (), ParseError<'_>> {
+    map(
+        // It's not the fastest implementation, but easiest to write.
+        // It passes initial whitespace two times.
+        many1(alt((
+            map(
+                pair(
+                    // white space
+                    multispace0,
+                    // ;;, ;;;, etc comment
+                    pair(tag(";;"), is_not("\r\n")),
+                ),
+                |_| (),
+            ),
+            map(multispace1, |_| ()),
+        ))),
+        |_| (),
+    )(inp)
+}
+
 #[cfg(test)]
 mod tests {
+    use super::*;
+    use crate::asserts::ServiceDefinition;
+
+    use pretty_assertions::assert_eq;
     use serde_json::json;
 
-    use super::*;
+    #[test]
+    fn test_multispace0_empty() {
+        let res = sexp_multispace0::<_, ()>("");
+        assert!(res.is_ok(), "{}", res.unwrap_err());
+    }
 
-    use crate::asserts::ServiceDefinition;
+    #[test]
+    fn test_multispace0_spaces() {
+        let res = sexp_multispace0::<_, ()>("  ");
+        assert!(res.is_ok(), "{}", res.unwrap_err());
+    }
+
+    #[test]
+    fn test_multispace0_comment() {
+        let res = sexp_multispace0::<_, ()>(";; this is comment");
+        assert!(res.is_ok(), "{}", res.unwrap_err());
+    }
+
+    #[test]
+    fn test_multispace0_comment_with_space() {
+        let res = sexp_multispace0::<_, ()>(" ;; ");
+        assert!(res.is_ok(), "{}", res.unwrap_err());
+    }
+
+    #[test]
+    fn test_multispace0_multiline() {
+        let res = sexp_multispace0::<_, ()>(" ;; \n ;;;; \n ");
+        assert!(res.is_ok(), "{}", res.unwrap_err());
+    }
+
+    #[test]
+    fn test_multispace1_empty() {
+        let res = sexp_multispace1("".into());
+        assert!(res.is_err());
+    }
+
+    #[test]
+    fn test_multispace1_space() {
+        let res = sexp_multispace1(" ".into());
+        assert!(res.is_ok(), "{}", res.unwrap_err());
+    }
+
+    #[test]
+    fn test_multispace1_comment() {
+        let res = sexp_multispace1(" ;; ".into());
+        assert!(res.is_ok(), "{}", res.unwrap_err());
+    }
+
+    #[test]
+    fn test_multispace1_multiline() {
+        let res = sexp_multispace1(" ;; \n ;;;; \n ".into());
+        assert!(res.is_ok(), "{}", res.unwrap_err());
+    }
 
     #[test]
     fn test_symbol() {
@@ -516,4 +627,37 @@ mod tests {
         let res = Sexp::from_str(sexp_str);
         assert!(res.is_ok(), "{:?}", res);
     }
+
+    #[test]
+    fn test_comments() {
+        let sexp_str = r#" ;; One comment
+( ;;; Second comment
+  ;; The third one
+  (par ;;;; Comment comment comment
+    ;;;; Comment comment comment
+    (null)  ;;;;; Comment
+    (fail  ;; Fails
+        1    ;; Retcode
+        "test"  ;; Message
+        ;; Nothing more
+    )
+  )   ;;;;; Comment
+  ;;;;; Comment
+ )  ;;;;; Comment
+;;; Comment
+"#;
+        let res = Sexp::from_str(sexp_str);
+        assert_eq!(
+            res,
+            Ok(Sexp::list(vec![Sexp::list(vec![
+                Sexp::symbol("par"),
+                Sexp::list(vec![Sexp::symbol("null"),]),
+                Sexp::list(vec![
+                    Sexp::symbol("fail"),
+                    Sexp::symbol("1"),
+                    Sexp::string("test"),
+                ]),
+            ])]))
+        );
+    }
 }