feat! don't allow indented scenario steps

Some day we will have syntax for continuing a step to the next line.
This change makes it easier to introduce that syntax, without a
breaking change.

Sponsored-by: author

2 files changed, 9 insertions, 1 deletions

diff --git a/src/error.rs b/src/error.rs
index db85e83..93a828a 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -10,6 +10,10 @@ use thiserror::Error;
 /// Define all the kinds of errors any part of this crate can return.
 #[derive(Debug, Error)]
 pub enum SubplotError {
+    /// Scenario step does not start at the beginning of the line.
+    #[error("Scenario step is indented: {0}")]
+    NotAtBoln(String),
+
     /// Document has non-fatal errors.
     #[error("Document has {0} warnings.")]
     Warnings(usize),
diff --git a/src/steps.rs b/src/steps.rs
index b0a15e9..1005ad8 100644
--- a/src/steps.rs
+++ b/src/steps.rs
@@ -51,6 +51,10 @@ impl ScenarioStep {
         text: &str,
         default: Option<StepKind>,
     ) -> Result<ScenarioStep, SubplotError> {
+        if text.trim_start() != text {
+            return Err(SubplotError::NotAtBoln(text.into()));
+        }
+
         let mut words = text.split_whitespace();
 
         let keyword = match words.next() {
@@ -126,7 +130,7 @@ mod test {
 
     #[test]
     fn parses_given_with_extra_spaces() {
-        let step = ScenarioStep::new_from_str("   given     I   am   Tomjon   ", None).unwrap();
+        let step = ScenarioStep::new_from_str("given     I   am   Tomjon   ", None).unwrap();
         assert_eq!(step.kind(), StepKind::Given);
         assert_eq!(step.text(), "I am Tomjon");
     }