Merge #5011

5011: Simplify fixtures r=matklad a=matklad

bors r+
🤖

Co-authored-by: Aleksey Kladov <[email protected]>

1 files changed, 216 insertions, 0 deletions

diff --git a/crates/test_utils/src/fixture.rs b/crates/test_utils/src/fixture.rs
new file mode 100644
index 000000000..9108e49d9
--- /dev/null
+++ b/crates/test_utils/src/fixture.rs
@@ -0,0 +1,216 @@
+//! Defines `Fixture` -- a convenient way to describe the initial state of
+//! rust-analyzer database from a single string.
+
+use rustc_hash::FxHashMap;
+use stdx::split1;
+
+#[derive(Debug, Eq, PartialEq)]
+pub struct Fixture {
+    pub path: String,
+    pub text: String,
+    pub crate_name: Option<String>,
+    pub deps: Vec<String>,
+    pub cfg_atoms: Vec<String>,
+    pub cfg_key_values: Vec<(String, String)>,
+    pub edition: Option<String>,
+    pub env: FxHashMap<String, String>,
+}
+
+impl Fixture {
+    /// Parses text which looks like this:
+    ///
+    ///  ```not_rust
+    ///  //- some meta
+    ///  line 1
+    ///  line 2
+    ///  // - other meta
+    ///  ```
+    pub fn parse(ra_fixture: &str) -> Vec<Fixture> {
+        let fixture = indent_first_line(ra_fixture);
+        let margin = fixture_margin(&fixture);
+
+        let mut lines = fixture
+        .split('\n') // don't use `.lines` to not drop `\r\n`
+        .enumerate()
+        .filter_map(|(ix, line)| {
+            if line.len() >= margin {
+                assert!(line[..margin].trim().is_empty());
+                let line_content = &line[margin..];
+                if !line_content.starts_with("//-") {
+                    assert!(
+                        !line_content.contains("//-"),
+                        r#"Metadata line {} has invalid indentation. All metadata lines need to have the same indentation.
+The offending line: {:?}"#,
+                        ix,
+                        line
+                    );
+                }
+                Some(line_content)
+            } else {
+                assert!(line.trim().is_empty());
+                None
+            }
+        });
+
+        let mut res: Vec<Fixture> = Vec::new();
+        for line in lines.by_ref() {
+            if line.starts_with("//-") {
+                let meta = Fixture::parse_single(line);
+                res.push(meta)
+            } else if let Some(entry) = res.last_mut() {
+                entry.text.push_str(line);
+                entry.text.push('\n');
+            }
+        }
+        res
+    }
+
+    //- /lib.rs crate:foo deps:bar,baz cfg:foo=a,bar=b env:OUTDIR=path/to,OTHER=foo
+    pub fn parse_single(meta: &str) -> Fixture {
+        assert!(meta.starts_with("//-"));
+        let meta = meta["//-".len()..].trim();
+        let components = meta.split_ascii_whitespace().collect::<Vec<_>>();
+
+        let path = components[0].to_string();
+        assert!(path.starts_with("/"));
+
+        let mut krate = None;
+        let mut deps = Vec::new();
+        let mut edition = None;
+        let mut cfg_atoms = Vec::new();
+        let mut cfg_key_values = Vec::new();
+        let mut env = FxHashMap::default();
+        for component in components[1..].iter() {
+            let (key, value) = split1(component, ':').unwrap();
+            match key {
+                "crate" => krate = Some(value.to_string()),
+                "deps" => deps = value.split(',').map(|it| it.to_string()).collect(),
+                "edition" => edition = Some(value.to_string()),
+                "cfg" => {
+                    for entry in value.split(',') {
+                        match split1(entry, '=') {
+                            Some((k, v)) => cfg_key_values.push((k.to_string(), v.to_string())),
+                            None => cfg_atoms.push(entry.to_string()),
+                        }
+                    }
+                }
+                "env" => {
+                    for key in value.split(',') {
+                        if let Some((k, v)) = split1(key, '=') {
+                            env.insert(k.into(), v.into());
+                        }
+                    }
+                }
+                _ => panic!("bad component: {:?}", component),
+            }
+        }
+
+        Fixture {
+            path,
+            text: String::new(),
+            crate_name: krate,
+            deps,
+            cfg_atoms,
+            cfg_key_values,
+            edition,
+            env,
+        }
+    }
+}
+
+/// Adjusts the indentation of the first line to the minimum indentation of the rest of the lines.
+/// This allows fixtures to start off in a different indentation, e.g. to align the first line with
+/// the other lines visually:
+/// ```
+/// let fixture = "//- /lib.rs
+///                mod foo;
+///                //- /foo.rs
+///                fn bar() {}
+/// ";
+/// assert_eq!(fixture_margin(fixture),
+/// "               //- /lib.rs
+///                mod foo;
+///                //- /foo.rs
+///                fn bar() {}
+/// ")
+/// ```
+fn indent_first_line(fixture: &str) -> String {
+    if fixture.is_empty() {
+        return String::new();
+    }
+    let mut lines = fixture.lines();
+    let first_line = lines.next().unwrap();
+    if first_line.contains("//-") {
+        let rest = lines.collect::<Vec<_>>().join("\n");
+        let fixed_margin = fixture_margin(&rest);
+        let fixed_indent = fixed_margin - indent_len(first_line);
+        format!("\n{}{}\n{}", " ".repeat(fixed_indent), first_line, rest)
+    } else {
+        fixture.to_owned()
+    }
+}
+
+fn fixture_margin(fixture: &str) -> usize {
+    fixture
+        .lines()
+        .filter(|it| it.trim_start().starts_with("//-"))
+        .map(indent_len)
+        .next()
+        .expect("empty fixture")
+}
+
+fn indent_len(s: &str) -> usize {
+    s.len() - s.trim_start().len()
+}
+
+#[test]
+#[should_panic]
+fn parse_fixture_checks_further_indented_metadata() {
+    Fixture::parse(
+        r"
+        //- /lib.rs
+          mod bar;
+
+          fn foo() {}
+          //- /bar.rs
+          pub fn baz() {}
+          ",
+    );
+}
+
+#[test]
+fn parse_fixture_can_handle_dedented_first_line() {
+    let fixture = "//- /lib.rs
+                   mod foo;
+                   //- /foo.rs
+                   struct Bar;
+";
+    assert_eq!(
+        Fixture::parse(fixture),
+        Fixture::parse(
+            "//- /lib.rs
+mod foo;
+//- /foo.rs
+struct Bar;
+"
+        )
+    )
+}
+
+#[test]
+fn parse_fixture_gets_full_meta() {
+    let parsed = Fixture::parse(
+        r"
+    //- /lib.rs crate:foo deps:bar,baz cfg:foo=a,bar=b,atom env:OUTDIR=path/to,OTHER=foo
+    mod m;
+    ",
+    );
+    assert_eq!(1, parsed.len());
+
+    let meta = &parsed[0];
+    assert_eq!("mod m;\n\n", meta.text);
+
+    assert_eq!("foo", meta.crate_name.as_ref().unwrap());
+    assert_eq!("/lib.rs", meta.path);
+    assert_eq!(2, meta.env.len());
+}