tests: verify that Subplot reports specific errors with location

Sponsored-by: author

4 files changed, 114 insertions, 20 deletions

diff --git a/src/doc.rs b/src/doc.rs
index f08f795..fe263ad 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -104,20 +104,20 @@ impl Document {
     {
         let meta = Metadata::from_yaml_metadata(basedir, yamlmeta, template)?;
         trace!("metadata from YAML: {:#?}", meta);
-        let files = Self::all_files(&markdowns);
+        let files = Self::all_files(&markdowns)?;
         let doc = Document::new(subplot, markdowns, meta, files, style);
         trace!("Loaded from JSON OK");
         Ok(doc)
     }
 
-    fn all_files(markdowns: &[Markdown]) -> EmbeddedFiles {
+    fn all_files(markdowns: &[Markdown]) -> Result<EmbeddedFiles, SubplotError> {
         let mut files = EmbeddedFiles::default();
         for md in markdowns {
-            for file in md.embedded_files().files() {
+            for file in md.embedded_files()?.files() {
                 files.push(file.clone());
             }
         }
-        files
+        Ok(files)
     }
 
     /// Construct a Document from a named file.
diff --git a/src/html.rs b/src/html.rs
index b39872b..d9788d9 100644
--- a/src/html.rs
+++ b/src/html.rs
@@ -681,7 +681,7 @@ pub enum HtmlError {
 
     /// Input contains an attempt to use a definition list in
     /// Markdown.
-    #[error("attempt to use definition lists in Markdown: {0}")]
+    #[error("{0}: attempt to use definition lists in Markdown")]
     DefinitionList(Location),
 
     /// String formatting error. This is likely a programming error.
diff --git a/src/md.rs b/src/md.rs
index 02a827b..02efa0c 100644
--- a/src/md.rs
+++ b/src/md.rs
@@ -142,16 +142,16 @@ impl Markdown {
 
     /// Find embedded files.
     // FIXME: this should return a result
-    pub fn embedded_files(&self) -> EmbeddedFiles {
+    pub fn embedded_files(&self) -> Result<EmbeddedFiles, MdError> {
         let mut files = EmbeddedFiles::default();
 
         for e in Self::visit(&self.html) {
-            if let Ok(file) = embedded_file(e) {
+            if let MaybeEmbeddedFile::IsFile(file) = embedded_file(e)? {
                 files.push(file);
             }
         }
 
-        files
+        Ok(files)
     }
 }
 
@@ -175,21 +175,23 @@ impl StructureElement {
     }
 }
 
-fn embedded_file(e: &Element) -> Result<EmbeddedFile, MdError> {
+enum MaybeEmbeddedFile {
+    IsFile(EmbeddedFile),
+    NotFile,
+}
+
+fn embedded_file(e: &Element) -> Result<MaybeEmbeddedFile, MdError> {
     if e.tag() != ElementTag::Pre {
-        return Err(MdError::NotCodeBlockElement(
-            e.tag().name().to_string(),
-            e.location(),
-        ));
+        return Ok(MaybeEmbeddedFile::NotFile);
     }
 
     if !e.has_attr("class", "file") {
-        return Err(MdError::NotFile(e.location()));
+        return Ok(MaybeEmbeddedFile::NotFile);
     }
 
     let id = e.attr("id");
     if id.is_none() {
-        return Err(MdError::NoId(e.location()));
+        return Ok(MaybeEmbeddedFile::NotFile);
     }
     let id = id.unwrap();
     if id.value().is_none() {
@@ -212,7 +214,8 @@ fn embedded_file(e: &Element) -> Result<EmbeddedFile, MdError> {
     if contents.ends_with('\n') {
         contents.truncate(contents.len() - 1);
     }
-    match AddNewline::parse(e.attr("add-newline"), e.location())? {
+    let addnl = AddNewline::parse(e.attr("add-newline"), e.location());
+    match addnl? {
         AddNewline::No => {
             // Newline already isn't there.
         }
@@ -228,7 +231,12 @@ fn embedded_file(e: &Element) -> Result<EmbeddedFile, MdError> {
         }
     };
 
-    Ok(EmbeddedFile::new(id.into(), contents))
+    eprintln!("ok");
+
+    Ok(MaybeEmbeddedFile::IsFile(EmbeddedFile::new(
+        id.into(),
+        contents,
+    )))
 }
 
 #[derive(Debug, Eq, PartialEq, Copy, Clone)]
@@ -426,7 +434,7 @@ pub enum MdError {
     NoIdValue(Location),
 
     /// Value ofv add-newline attribute ie not understood.
-    #[error("{0}: value of add-newline attirubte is not understood: {0}")]
+    #[error("{1}: value of add-newline attribute is not understood: {0}")]
     BadAddNewline(String, Location),
 }
 
@@ -637,7 +645,7 @@ given ABBA
     fn finds_no_embedded_files_in_empty_doc() {
         let md = Markdown::new_from_str(Path::new(""), "").unwrap();
         let files = md.embedded_files();
-        assert!(files.files().is_empty());
+        assert!(files.unwrap().files().is_empty());
     }
 
     #[test]
@@ -651,7 +659,7 @@ hello, world
 "#,
         )
         .unwrap();
-        let files = md.embedded_files();
+        let files = md.embedded_files().unwrap();
         assert_eq!(files.files().len(), 1);
         let file = files.files().get(0).unwrap();
         assert_eq!(file.filename(), "fileid");
diff --git a/subplot.md b/subplot.md
index 9929e8b..129fc8b 100644
--- a/subplot.md
+++ b/subplot.md
@@ -3566,3 +3566,89 @@ This is a test file.
 ~~~{#expected.txt .file}
 This is a test file.
 ~~~
+## Mistakes in markdown
+
+When there are mistakes in the markdown input, Subplot should report
+the location (filename, line, column) where the mistake is, and what
+the mistake is. The scenarios in this section verify that.
+
+### Scenario before the first heading
+
+_Requirement: A scenario must follow a heading._
+
+Justification: the heading can be used as the title for the scenario.
+
+~~~scenario
+given an installed subplot
+given file scenario-before-heading.subplot
+given file scenario-before-heading.md
+when I try to run subplot docgen scenario-before-heading.subplot -o /dev/null
+then command fails
+then stderr contains "ERROR: scenario-before-heading.md:1:1: first scenario is before first heading"
+~~~
+
+~~~{#scenario-before-heading.subplot .file .yaml}
+title: Foo
+markdowns:
+  - scenario-before-heading.md
+~~~
+
+~~~~~~{#scenario-before-heading.md .file .markdown}
+~~~scenario
+~~~
+~~~~~~
+
+### Attempt to use definition list
+
+_Requirement: Attempt to use definition lists is reported._
+
+Justification: the markdown parser we use in Subplot doesn't support
+them, and it would be unhelpful to not tell the user if they try to
+use them.
+
+~~~scenario
+given an installed subplot
+given file dl.subplot
+given file dl.md
+when I try to run subplot docgen dl.subplot -o /dev/null
+then command fails
+then stderr contains "ERROR: dl.md:3:1: attempt to use definition lists in Markdown"
+~~~
+
+~~~{#dl.subplot .file .yaml}
+title: Foo
+markdowns:
+  - dl.md
+~~~
+
+~~~~~~{#dl.md .file .markdown}
+# Foo
+
+Some term
+: Definition of term.
+~~~~~~
+
+### Bad "add-newline" value
+
+_Requirement: Only specific values for the "add-newline" attribute are
+allowed for an embedded file._
+
+~~~scenario
+given an installed subplot
+given file add-newline.subplot
+given file add-newline.md
+when I try to run subplot docgen add-newline.subplot -o /dev/null
+then command fails
+then stderr contains "ERROR: add-newline.md:1:1: value of add-newline attribute is not understood: xyzzy"
+~~~
+
+~~~{#add-newline.subplot .file .yaml}
+title: Foo
+markdowns:
+  - add-newline.md
+~~~
+
+~~~~~~{#add-newline.md .file .markdown}
+~~~{#foo.txt .file add-newline=xyzzy}
+~~~
+~~~~~~