booksniff, and one place for the parts every tool shares

crates/booksniff/tests/cli.rs

@@ -0,0 +1,95 @@
+//! The tool as a caller meets it: files in, records and an exit code out.
+
+use std::path::PathBuf;
+use std::process::{Command, Output};
+
+fn run(args: &[&str]) -> Output {
+    Command::new(env!("CARGO_BIN_EXE_booksniff"))
+        .args(args)
+        .output()
+        .expect("the binary should run")
+}
+
+fn written(name: &str, bytes: &[u8]) -> PathBuf {
+    let dir = std::env::temp_dir().join("booksniff-tests");
+    std::fs::create_dir_all(&dir).expect("a writable temp directory");
+    let path = dir.join(name);
+    std::fs::write(&path, bytes).expect("a writable path");
+    path
+}
+
+fn padded(head: &[u8]) -> Vec<u8> {
+    let mut out = head.to_vec();
+    out.resize(8192, b'x');
+    out
+}
+
+#[test]
+fn a_file_it_recognises_comes_back_as_a_record() {
+    let path = written("book.pdf", &padded(b"%PDF-1.7\n"));
+    let out = run(&[path.to_str().expect("utf-8 path")]);
+    assert_eq!(out.status.code(), Some(0));
+
+    let doc: serde_json::Value = serde_json::from_slice(&out.stdout).expect("one JSON record");
+    assert_eq!(doc["kind"], "pdf");
+    assert_eq!(doc["declared_ext"], "pdf");
+    assert_eq!(doc["bytes"], 8192);
+    assert!(out.stderr.is_empty());
+}
+
+#[test]
+fn a_file_it_cannot_place_answers_no() {
+    let path = written("mystery.bin", &padded(&[0x00, 0x01, 0x02]));
+    let out = run(&[path.to_str().expect("utf-8 path")]);
+    assert_eq!(out.status.code(), Some(1), "unknown must answer no");
+    let doc: serde_json::Value = serde_json::from_slice(&out.stdout).expect("one JSON record");
+    assert_eq!(doc["kind"], "unknown");
+}
+
+#[test]
+fn several_files_come_back_as_several_records() {
+    let one = written("one.pdf", &padded(b"%PDF-1.7"));
+    let two = written("two.djvu", &padded(b"AT&TFORM"));
+    let out = run(&[
+        one.to_str().expect("utf-8 path"),
+        two.to_str().expect("utf-8 path"),
+    ]);
+    let kinds: Vec<String> = String::from_utf8(out.stdout)
+        .expect("utf-8")
+        .lines()
+        .map(|line| {
+            serde_json::from_str::<serde_json::Value>(line).expect("valid JSON")["kind"].to_string()
+        })
+        .collect();
+    assert_eq!(kinds, ["\"pdf\"", "\"djvu\""]);
+}
+
+#[test]
+fn a_file_that_is_not_there_is_an_io_error_and_the_rest_still_run() {
+    let path = written("kept.pdf", &padded(b"%PDF-1.7"));
+    let out = run(&[
+        "/definitely/not/here.pdf",
+        path.to_str().expect("utf-8 path"),
+    ]);
+    assert_eq!(out.status.code(), Some(74));
+    assert!(!out.stderr.is_empty());
+    // The readable file was still identified, on stdout, uncontaminated.
+    let doc: serde_json::Value = serde_json::from_slice(&out.stdout).expect("one JSON record");
+    assert_eq!(doc["kind"], "pdf");
+}
+
+#[test]
+fn the_plain_form_is_for_a_person() {
+    let path = written("lying.pdf", &padded(b"AT&TFORM"));
+    let out = run(&["--plain", path.to_str().expect("utf-8 path")]);
+    let said = String::from_utf8(out.stdout).expect("utf-8");
+    assert!(said.starts_with("djvu\t"), "{said}");
+    assert!(said.contains("named .pdf"), "{said}");
+}
+
+#[test]
+fn no_files_named_is_a_usage_error() {
+    let out = run(&[]);
+    assert_eq!(out.status.code(), Some(64), "usage errors exit 64");
+    assert!(out.stdout.is_empty());
+}