chore: refactor ahead of supporting more conversion types

tests/job_and_format_tests.rs

@@ -0,0 +1,40 @@
+use std::path::PathBuf;
+
+use cbz2pdf::formats::FormatId;
+use cbz2pdf::job::Job;
+
+#[test]
+fn detect_from_path_recognizes_extensions() {
+    let cbz = PathBuf::from("/tmp/book.cbz");
+    let pdf = PathBuf::from("/tmp/book.pdf");
+    assert_eq!(FormatId::detect_from_path(&cbz), Some(FormatId::Cbz));
+    assert_eq!(FormatId::detect_from_path(&pdf), Some(FormatId::Pdf));
+    assert_eq!(
+        FormatId::detect_from_path(&PathBuf::from("/tmp/book.txt")),
+        None
+    );
+}
+
+#[test]
+fn job_new_sets_output_extension() {
+    let input = PathBuf::from("/tmp/book.cbz");
+    let outdir = PathBuf::from("/tmp");
+    let job = Job::new(input.clone(), outdir.clone(), FormatId::Cbz, FormatId::Pdf);
+    assert!(job.output_path.ends_with("book.pdf"));
+
+    let job2 = Job::new(
+        PathBuf::from("/tmp/book.pdf"),
+        outdir,
+        FormatId::Pdf,
+        FormatId::Cbz,
+    );
+    assert!(job2.output_path.ends_with("book.cbz"));
+}
+
+#[test]
+fn format_capabilities_consistent() {
+    assert!(FormatId::Cbz.can_read());
+    assert!(!FormatId::Cbz.can_write());
+    assert!(FormatId::Pdf.can_write());
+    assert!(!FormatId::Pdf.can_read());
+}