Add an example of an integration test

Very draft — but shows a reasonably scalable way to add integration tests. There are some TODOs at the top.

This would help with issues such as #531

cargo-insta/tests/main.rs

@@ -6,6 +6,8 @@ use std::process::{Command, Output};
 use insta::{assert_snapshot, Settings};
 use walkdir::WalkDir;
 
+mod new;
+
 struct OnDrop<F: FnOnce()>(Option<F>);
 
 impl<F: FnOnce()> Drop for OnDrop<F> {

cargo-insta/tests/new.rs

@@ -0,0 +1,213 @@
+use insta::assert_snapshot;
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+use std::process::Command;
+use tempfile::TempDir;
+
+// TODO:
+// - pull out the common parts — setting up the test
+// - how to handle compilation? We want each test to be independent, but we
+//   don't want to compile `insta` for each test. Maybe we can compile it once
+//   and copy the `target` directory for each test?
+
+#[test]
+fn test_json_inline_integration() {
+    let temp_dir = TempDir::new().unwrap();
+    let project_path = temp_dir.path();
+
+    // Get the absolute path to the current insta crate
+    let manifest_dir = env!("CARGO_MANIFEST_DIR");
+    let cargo_insta_path = PathBuf::from(manifest_dir).canonicalize().unwrap();
+    let insta_path = cargo_insta_path.parent().unwrap().join("insta");
+
+    // Create Cargo.toml
+    let cargo_toml = format!(
+        r#"
+[package]
+name = "test_json_inline"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+insta = {{ path = "{}", features=["json", "redactions"] }}
+serde = {{ version = "1.0", features = ["derive"] }}
+"#,
+        insta_path.to_str().unwrap()
+    );
+    fs::write(project_path.join("Cargo.toml"), cargo_toml).unwrap();
+
+    fs::create_dir(project_path.join("src")).unwrap();
+
+    let main_rs = r#"
+use serde::Serialize;
+
+#[derive(Serialize)]
+struct User {
+    id: u64,
+    email: String,
+}
+
+#[test]
+fn test_json_snapshot() {
+    let user = User {
+        id: 42,
+        email: "[email protected]".into(),
+    };
+    insta::assert_json_snapshot!(&user, {
+        ".id" => "[user_id]",
+    }, @"");
+}
+
+#[test]
+fn test_json_snapshot_trailing_comma() {
+    let user = User {
+        id: 42,
+        email: "[email protected]".into(),
+    };
+    insta::assert_compact_json_snapshot!(
+        &user,
+        @"",
+    );
+}
+
+#[test]
+fn test_json_snapshot_trailing_comma_redaction() {
+    let user = User {
+        id: 42,
+        email: "[email protected]".into(),
+    };
+    insta::assert_json_snapshot!(
+        &user,
+        {
+            ".id" => "[user_id]",
+        },
+        @"",
+    );
+}
+"#;
+
+    let dest = project_path.join("src").join("main.rs");
+    fs::write(dest.clone(), main_rs).unwrap();
+
+    // Run cargo-insta test
+    let output = Command::new(env!("CARGO_BIN_EXE_cargo-insta"))
+        .current_dir(project_path)
+        .arg("test")
+        .arg("--accept")
+        .output()
+        .expect("Failed to execute command");
+
+    // Check if the tests passed
+    assert!(
+        output.status.success(),
+        "Tests failed: {}\n{}",
+        String::from_utf8_lossy(&output.stdout),
+        String::from_utf8_lossy(&output.stderr)
+    );
+
+    let contents = fs::read_to_string(dest).unwrap();
+    assert_snapshot!(contents, @r#####"
+
+    use serde::Serialize;
+
+    #[derive(Serialize)]
+    struct User {
+        id: u64,
+        email: String,
+    }
+
+    #[test]
+    fn test_json_snapshot() {
+        let user = User {
+            id: 42,
+            email: "[email protected]".into(),
+        };
+        insta::assert_json_snapshot!(&user, {
+            ".id" => "[user_id]",
+        }, @r###"
+        {
+          "id": "[user_id]",
+          "email": "[email protected]"
+        }
+        "###);
+    }
+
+    #[test]
+    fn test_json_snapshot_trailing_comma() {
+        let user = User {
+            id: 42,
+            email: "[email protected]".into(),
+        };
+        insta::assert_compact_json_snapshot!(
+            &user,
+            @r###"{"id": 42, "email": "[email protected]"}"###,
+        );
+    }
+
+    #[test]
+    fn test_json_snapshot_trailing_comma_redaction() {
+        let user = User {
+            id: 42,
+            email: "[email protected]".into(),
+        };
+        insta::assert_json_snapshot!(
+            &user,
+            {
+                ".id" => "[user_id]",
+            },
+            @r###"
+        {
+          "id": "[user_id]",
+          "email": "[email protected]"
+        }
+        "###,
+        );
+    }
+    "#####);
+}
+
+// // Verify snapshots were created
+// let snapshot_dir = project_path
+//     .parent()
+//     .unwrap()
+//     .join("src")
+//     .join("snapshots")
+//     .to_owned()
+//     .as_path().;
+// assert!(
+//     snapshot_dir.exists(),
+//     "Snapshot directory was not created. Project structure:\n\n{}",
+//     list_directory_contents(&project_path.to_path_buf())
+// );
+
+// // Additional checks for snapshot files
+// let snapshot_files = fs::read_dir(&snapshot_dir)
+//     .expect("Failed to read snapshot directory")
+//     .filter_map(|entry| entry.ok())
+//     .map(|entry| entry.file_name().to_string_lossy().into_owned())
+//     .collect::<Vec<_>>();
+
+// assert!(
+//     !snapshot_files.is_empty(),
+//     "No snapshot files were created in the snapshot directory. Directory contents:\n\n{}",
+//     list_directory_contents(&snapshot_dir)
+// );
+// }
+// use ignore::WalkBuilder;
+// fn list_directory_contents(path: &PathBuf) -> String {
+//     // TODO: could use `find_snapshots` but would need to reorganize the crate a
+//     // bit given visibility
+//     WalkBuilder::new(path)
+//         // .into_iter()
+//         // .filter_entry(|e| e.ok())
+//         .filter_entry(|e| e.path().file_name() != Some(std::ffi::OsStr::new("target")))
+//         .build()
+//         .filter_map(|e| e.ok())
+//         .map(|entry| {
+//             let path = entry.path().strip_prefix(path).unwrap_or(entry.path());
+//             format!("{}{}", "  ".repeat(entry.depth()), path.display())
+//         })
+//         .collect::<Vec<_>>()
+//         .join("\n")
+// }