Feat/variable interpolation and capture

crates/utest-cli/Cargo.toml

@@ -10,5 +10,5 @@ path = "src/main.rs"
 [dependencies]
 clap = { version = "4.5.50", features = ["derive"] }
 utest-application = { path = "../utest-application" }
-utest-domain = { path = "../utest-domain" }
 utest-parser = { path = "../utest-parser" }
+utest-runtime = { path = "../utest-runtime" }

crates/utest-cli/src/main.rs

@@ -1,7 +1,7 @@
 //! Command-line interface for UTest.
 //!
 //! The `check` command validates a `.utest` source file without making HTTP
-//! requests. It reads the file, obtains predefined variable names from the
+//! requests. It reads the file, obtains predefined variables from the
 //! process environment and repeated `--var NAME=VALUE` arguments, and delegates
 //! the compiler pipeline to [`utest_application::check_source`].
 //!
@@ -25,8 +25,8 @@ use std::{fs, path::PathBuf, process::ExitCode};
 
 use clap::{Parser as ClapParser, Subcommand};
 use utest_application::{CheckDiagnostic, check_source};
-use utest_domain::VariableName;
 use utest_parser::{SourceText, ValidationContext};
+use utest_runtime::{VariableAssignment, VariableStore};
 
 /// Exit status used when source validation reports diagnostics.
 const CHECK_FAILED_EXIT_CODE: u8 = 3;
@@ -49,7 +49,7 @@ enum Command {
 
         /// Defines a variable for semantic checking (`NAME=VALUE`).
         #[arg(long = "var", value_name = "NAME=VALUE", value_parser = parse_variable)]
-        variables: Vec<VariableName>,
+        variables: Vec<VariableAssignment>,
     },
 }
 
@@ -63,9 +63,10 @@ fn main() -> ExitCode {
 
 /// Checks one file using CLI and environment variables as predefined names.
 ///
-/// Variable values are intentionally not interpreted at this stage because
-/// source checking only needs to establish whether referenced names exist.
-fn check(path: PathBuf, variables: Vec<VariableName>) -> ExitCode {
+/// Values are retained in the runtime store while source validation receives
+/// names only. Capture declarations that collide with predefined names are
+/// rejected by semantic validation.
+fn check(path: PathBuf, variables: Vec<VariableAssignment>) -> ExitCode {
     let content = match fs::read_to_string(&path) {
         Ok(content) => content,
         Err(error) => {
@@ -75,12 +76,10 @@ fn check(path: PathBuf, variables: Vec<VariableName>) -> ExitCode {
     };
 
     let source = SourceText::new(path.display().to_string(), content);
-    let environment_variables = std::env::vars_os()
-        .filter_map(|(name, _)| name.into_string().ok())
-        .filter_map(|name| VariableName::new(name).ok());
-    let context = ValidationContext::new()
-        .with_predefined_variables(environment_variables)
-        .with_predefined_variables(variables);
+    let mut variable_store = VariableStore::from_environment();
+    variable_store.apply_cli(variables);
+    let context =
+        ValidationContext::new().with_predefined_variables(variable_store.names().cloned());
     let report = check_source(&source, &context);
 
     if report.is_success() {
@@ -112,11 +111,8 @@ fn render_diagnostic(source: &SourceText, diagnostic: &CheckDiagnostic) {
 
 /// Validates the `NAME=VALUE` form accepted by `--var`.
 ///
-/// The name follows [`VariableName`] rules. The value may be empty and is
-/// ignored until runtime interpolation is implemented.
-fn parse_variable(raw: &str) -> Result<VariableName, String> {
-    let Some((name, _value)) = raw.split_once('=') else {
-        return Err("expected NAME=VALUE".to_owned());
-    };
-    VariableName::new(name).map_err(|error| error.to_string())
+/// Parsing splits at the first `=`, so values may be empty or contain `=`.
+fn parse_variable(raw: &str) -> Result<VariableAssignment, String> {
+    raw.parse::<VariableAssignment>()
+        .map_err(|error| error.to_string())
 }

crates/utest-cli/tests/check_command.rs

@@ -135,6 +135,24 @@ fn duplicate_var_names_are_accepted_as_one_predefined_name() {
     assert!(stderr(&output).is_empty());
 }
 
+#[test]
+fn predefined_cli_variable_cannot_be_redeclared_as_a_capture() {
+    let source = TemporaryFile::text(
+        "capture-collision.utest",
+        r#"test "capture" {
+            request GET "/"
+            expect { body { id: integer -> PREDEFINED } }
+        }"#,
+    );
+    let secret = "must-not-appear-in-diagnostics";
+    let output = run_check(source.path(), &["--var", &format!("PREDEFINED={secret}")]);
+
+    assert_eq!(output.status.code(), Some(3));
+    assert!(stdout(&output).is_empty());
+    assert!(stderr(&output).contains("variable `PREDEFINED` is already defined"));
+    assert!(!stderr(&output).contains(secret));
+}
+
 #[test]
 fn missing_and_invalid_var_arguments_are_clap_errors() {
     let source = TemporaryFile::text(

crates/utest-http/src/model.rs

@@ -19,6 +19,8 @@ pub enum ResolvedValue {
     String(String),
     /// Signed 64-bit integer.
     Integer(i64),
+    /// Unsigned 64-bit integer retained from a captured JSON response.
+    UnsignedInteger(u64),
     /// Double-precision number. The adapter rejects non-finite values.
     Number(f64),
     /// Boolean value.
@@ -49,6 +51,12 @@ impl From<i64> for ResolvedValue {
     }
 }
 
+impl From<u64> for ResolvedValue {
+    fn from(value: u64) -> Self {
+        Self::UnsignedInteger(value)
+    }
+}
+
 impl From<f64> for ResolvedValue {
     fn from(value: f64) -> Self {
         Self::Number(value)

crates/utest-http/src/reqwest_client.rs

@@ -183,6 +183,7 @@ fn wire_scalar(
     match value {
         ResolvedValue::String(value) => Ok(value.clone()),
         ResolvedValue::Integer(value) => Ok(value.to_string()),
+        ResolvedValue::UnsignedInteger(value) => Ok(value.to_string()),
         ResolvedValue::Number(value) if value.is_finite() => Ok(value.to_string()),
         ResolvedValue::Number(_) => Err(HttpError::invalid_request(format!(
             "a {location} number must be finite"
@@ -202,6 +203,7 @@ fn to_json(value: &ResolvedValue, depth: usize) -> Result<JsonValue, HttpError>
     match value {
         ResolvedValue::String(value) => Ok(JsonValue::String(value.clone())),
         ResolvedValue::Integer(value) => Ok(JsonValue::Number((*value).into())),
+        ResolvedValue::UnsignedInteger(value) => Ok(JsonValue::Number((*value).into())),
         ResolvedValue::Number(value) => JsonNumber::from_f64(*value)
             .map(JsonValue::Number)
             .ok_or_else(|| HttpError::invalid_request("a JSON number must be finite")),

crates/utest-http/tests/model_and_error.rs

@@ -20,6 +20,10 @@ fn resolved_value_supports_public_scalar_conversions() {
         ResolvedValue::String("owned".into())
     );
     assert_eq!(ResolvedValue::from(-42_i64), ResolvedValue::Integer(-42));
+    assert_eq!(
+        ResolvedValue::from(u64::MAX),
+        ResolvedValue::UnsignedInteger(u64::MAX)
+    );
     assert_eq!(ResolvedValue::from(3.5_f64), ResolvedValue::Number(3.5));
     assert_eq!(ResolvedValue::from(true), ResolvedValue::Boolean(true));
 }

crates/utest-http/tests/reqwest_client_integration.rs

@@ -150,10 +150,12 @@ async fn sends_all_methods_beneath_base_path_and_encodes_scalar_metadata() {
         let request = ResolvedHttpRequest::new(method, "/users/alice")
             .with_header("x-string", "direct value")
             .with_header("x-integer", -12_i64)
+            .with_header("x-unsigned", u64::MAX)
             .with_header("x-number", 1.25_f64)
             .with_header("x-boolean", true)
             .with_query_param("text", "a value")
             .with_query_param("integer", -4_i64)
+            .with_query_param("unsigned", u64::MAX)
             .with_query_param("number", 2.5_f64)
             .with_query_param("boolean", false)
             .with_query_param("nothing", ResolvedValue::Null);
@@ -165,11 +167,13 @@ async fn sends_all_methods_beneath_base_path_and_encodes_scalar_metadata() {
         let received = server.request.await.unwrap();
         let received = request_text(&received);
         assert!(received.starts_with(&format!(
-            "{} /api/users/alice?text=a+value&integer=-4&number=2.5&boolean=false&nothing=null HTTP/1.1\r\n",
-            method.as_str()
+            "{} /api/users/alice?text=a+value&integer=-4&unsigned={}&number=2.5&boolean=false&nothing=null HTTP/1.1\r\n",
+            method.as_str(),
+            u64::MAX,
         )));
         assert!(received.contains("x-string: direct value\r\n"));
         assert!(received.contains("x-integer: -12\r\n"));
+        assert!(received.contains(&format!("x-unsigned: {}\r\n", u64::MAX)));
         assert!(received.contains("x-number: 1.25\r\n"));
         assert!(received.contains("x-boolean: true\r\n"));
     }
@@ -251,6 +255,7 @@ async fn encodes_all_request_bodies_and_respects_content_type_override() {
     let mut object = IndexMap::new();
     object.insert("string".into(), "value".into());
     object.insert("integer".into(), (-2_i64).into());
+    object.insert("unsigned".into(), u64::MAX.into());
     object.insert("number".into(), 3.5_f64.into());
     object.insert("boolean".into(), true.into());
     object.insert("null".into(), ResolvedValue::Null);
@@ -262,6 +267,7 @@ async fn encodes_all_request_bodies_and_respects_content_type_override() {
     let mut form = IndexMap::new();
     form.insert("name".into(), "Ada Lovelace".into());
     form.insert("count".into(), 2_i64.into());
+    form.insert("unsigned".into(), u64::MAX.into());
     form.insert("ratio".into(), 1.5_f64.into());
     form.insert("active".into(), false.into());
     form.insert("empty".into(), ResolvedValue::Null);
@@ -270,7 +276,7 @@ async fn encodes_all_request_bodies_and_respects_content_type_override() {
         (
             ResolvedRequestBody::Json(ResolvedValue::Object(object)),
             "application/json",
-            br#"{"string":"value","integer":-2,"number":3.5,"boolean":true,"null":null,"array":[1]}"#.as_slice(),
+            br#"{"string":"value","integer":-2,"unsigned":18446744073709551615,"number":3.5,"boolean":true,"null":null,"array":[1]}"#.as_slice(),
             None,
         ),
         (
@@ -282,7 +288,7 @@ async fn encodes_all_request_bodies_and_respects_content_type_override() {
         (
             ResolvedRequestBody::FormData(form),
             "application/x-www-form-urlencoded",
-            b"name=Ada+Lovelace&count=2&ratio=1.5&active=false&empty=null".as_slice(),
+            b"name=Ada+Lovelace&count=2&unsigned=18446744073709551615&ratio=1.5&active=false&empty=null".as_slice(),
             None,
         ),
         (

crates/utest-runtime/Cargo.toml

@@ -4,3 +4,10 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+bytes = "1.10"
+indexmap = "2.14"
+serde_json = "1.0"
+thiserror = "2.0"
+utest-assertion = { path = "../utest-assertion" }
+utest-domain = { path = "../utest-domain" }
+utest-http = { path = "../utest-http" }