Add kinds chapter

coracle-lib/tests/kinds.rs

@@ -0,0 +1,77 @@
+use coracle_lib::kinds::{is_addressable, is_ephemeral, is_regular, is_replaceable};
+use coracle_lib::kinds::KindError;
+
+// --- Free function classification tests ---
+
+#[test]
+fn regular_kind_1() {
+    assert!(is_regular(1));
+}
+
+#[test]
+fn regular_kind_9999() {
+    assert!(is_regular(9999));
+}
+
+#[test]
+fn kind_0_is_replaceable_not_regular() {
+    assert!(!is_regular(0));
+    assert!(is_replaceable(0));
+}
+
+#[test]
+fn kind_3_is_replaceable_not_regular() {
+    assert!(!is_regular(3));
+    assert!(is_replaceable(3));
+}
+
+#[test]
+fn replaceable_range() {
+    assert!(is_replaceable(10_000));
+    assert!(is_replaceable(19_999));
+    assert!(!is_replaceable(20_000));
+}
+
+#[test]
+fn ephemeral_range() {
+    assert!(is_ephemeral(20_000));
+    assert!(is_ephemeral(29_999));
+    assert!(!is_ephemeral(30_000));
+}
+
+#[test]
+fn addressable_range() {
+    assert!(is_addressable(30_000));
+    assert!(is_addressable(39_999));
+    assert!(!is_addressable(40_000));
+}
+
+#[test]
+fn ranges_are_mutually_exclusive_for_regular() {
+    for k in [1, 100, 5000, 9999] {
+        assert!(is_regular(k));
+        assert!(!is_replaceable(k));
+        assert!(!is_ephemeral(k));
+        assert!(!is_addressable(k));
+    }
+}
+
+#[test]
+fn high_kinds_are_none_of_the_above() {
+    assert!(!is_regular(40_000));
+    assert!(!is_replaceable(40_000));
+    assert!(!is_ephemeral(40_000));
+    assert!(!is_addressable(40_000));
+}
+
+#[test]
+fn kind_error_display() {
+    let err = KindError::WrongKind {
+        expected: 5,
+        got: 1,
+    };
+    assert_eq!(err.to_string(), "expected kind 5, got 1");
+
+    let err = KindError::InvalidContent("bad json".into());
+    assert_eq!(err.to_string(), "invalid content for kind: bad json");
+}