Add some basic tests

Cargo.toml

@@ -43,6 +43,7 @@ red_knot_workspace = { path = "crates/red_knot_workspace" }
 aho-corasick = { version = "1.1.3" }
 annotate-snippets = { version = "0.9.2", features = ["color"] }
 anyhow = { version = "1.0.80" }
+assert_fs = { version = "1.1.0" }
 argfile = { version = "0.2.0" }
 bincode = { version = "1.3.3" }
 bitflags = { version = "2.5.0" }

crates/ruff/Cargo.toml

@@ -62,8 +62,11 @@ wild = { workspace = true }
 [dev-dependencies]
 # Enable test rules during development
 ruff_linter = { workspace = true, features = ["clap", "test-rules"] }
+
+assert_fs = { workspace = true }
 # Avoid writing colored snapshots when running tests from the terminal
 colored = { workspace = true, features = ["no-color"] }
+indoc = { workspace = true }
 insta = { workspace = true, features = ["filters", "json"] }
 insta-cmd = { workspace = true }
 tempfile = { workspace = true }

crates/ruff/tests/analyze_graph.rs

@@ -0,0 +1,197 @@
+//! Tests the interaction of the `analyze graph` command.
+
+#![cfg(not(target_family = "wasm"))]
+
+use assert_fs::prelude::*;
+use std::process::Command;
+use std::str;
+
+use anyhow::Result;
+use assert_fs::fixture::ChildPath;
+use insta_cmd::{assert_cmd_snapshot, get_cargo_bin};
+use tempfile::TempDir;
+
+fn command() -> Command {
+    let mut command = Command::new(get_cargo_bin("ruff"));
+    command.arg("analyze");
+    command.arg("graph");
+    command.arg("--preview");
+    command
+}
+
+#[test]
+fn dependencies() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let root = ChildPath::new(tempdir.path());
+
+    root.child("ruff").child("__init__.py").write_str("")?;
+    root.child("ruff")
+        .child("a.py")
+        .write_str(indoc::indoc! {r#"
+        import ruff.b
+    "#})?;
+    root.child("ruff")
+        .child("b.py")
+        .write_str(indoc::indoc! {r#"
+        from ruff import c
+    "#})?;
+    root.child("ruff")
+        .child("c.py")
+        .write_str(indoc::indoc! {r#"
+        from . import d
+    "#})?;
+    root.child("ruff")
+        .child("d.py")
+        .write_str(indoc::indoc! {r#"
+        from .e import f
+    "#})?;
+    root.child("ruff")
+        .child("e.py")
+        .write_str(indoc::indoc! {r#"
+        def f(): pass
+    "#})?;
+
+    assert_cmd_snapshot!(command().current_dir(&root), @r###"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        {
+          "ruff/__init__.py": [],
+          "ruff/a.py": [
+            "ruff/b.py"
+          ],
+          "ruff/b.py": [
+            "ruff/c.py"
+          ],
+          "ruff/c.py": [
+            "ruff/d.py"
+          ],
+          "ruff/d.py": [
+            "ruff/e.py"
+          ],
+          "ruff/e.py": []
+        }
+
+        ----- stderr -----
+        "###);
+
+    Ok(())
+}
+
+#[test]
+fn dependents() -> Result<()> {
+    let tempdir = TempDir::new()?;
+
+    let root = ChildPath::new(tempdir.path());
+
+    root.child("ruff").child("__init__.py").write_str("")?;
+    root.child("ruff")
+        .child("a.py")
+        .write_str(indoc::indoc! {r#"
+        import ruff.b
+    "#})?;
+    root.child("ruff")
+        .child("b.py")
+        .write_str(indoc::indoc! {r#"
+        from ruff import c
+    "#})?;
+    root.child("ruff")
+        .child("c.py")
+        .write_str(indoc::indoc! {r#"
+        from . import d
+    "#})?;
+    root.child("ruff")
+        .child("d.py")
+        .write_str(indoc::indoc! {r#"
+        from .e import f
+    "#})?;
+    root.child("ruff")
+        .child("e.py")
+        .write_str(indoc::indoc! {r#"
+        def f(): pass
+    "#})?;
+
+    assert_cmd_snapshot!(command().arg("--direction").arg("dependents").current_dir(&root), @r###"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        {
+          "ruff/__init__.py": [],
+          "ruff/a.py": [],
+          "ruff/b.py": [
+            "ruff/a.py"
+          ],
+          "ruff/c.py": [
+            "ruff/b.py"
+          ],
+          "ruff/d.py": [
+            "ruff/c.py"
+          ],
+          "ruff/e.py": [
+            "ruff/d.py"
+          ]
+        }
+
+        ----- stderr -----
+        "###);
+
+    Ok(())
+}
+
+#[test]
+fn string_detection() -> Result<()> {
+    let tempdir = TempDir::new()?;
+
+    let root = ChildPath::new(tempdir.path());
+
+    root.child("ruff").child("__init__.py").write_str("")?;
+    root.child("ruff")
+        .child("a.py")
+        .write_str(indoc::indoc! {r#"
+        import ruff.b
+    "#})?;
+    root.child("ruff")
+        .child("b.py")
+        .write_str(indoc::indoc! {r#"
+        import importlib
+
+        importlib.import_module("ruff.c")
+    "#})?;
+    root.child("ruff").child("c.py").write_str("")?;
+
+    assert_cmd_snapshot!(command().current_dir(&root), @r###"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        {
+          "ruff/__init__.py": [],
+          "ruff/a.py": [
+            "ruff/b.py"
+          ],
+          "ruff/b.py": [],
+          "ruff/c.py": []
+        }
+
+        ----- stderr -----
+        "###);
+
+    assert_cmd_snapshot!(command().arg("--detect-string-imports").current_dir(&root), @r###"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        {
+          "ruff/__init__.py": [],
+          "ruff/a.py": [
+            "ruff/b.py"
+          ],
+          "ruff/b.py": [
+            "ruff/c.py"
+          ],
+          "ruff/c.py": []
+        }
+
+        ----- stderr -----
+        "###);
+
+    Ok(())
+}