(ns expand-test
  (:require [expand :as sut]
            [clojure.test :as t]
            [clojure.spec.alpha :as s]))

(t/deftest scheme-base-env-test
  (t/is (s/valid? ::sut/environment sut/scheme-base-env)))

(t/deftest symtable-for-env-test
  (t/is (s/valid? ::sut/symtable (sut/symtable-for-env sut/scheme-base-env))))

(t/deftest nearest-test
  (t/is (= [:primitive 'lambda]
           (sut/lookup ['lambda #{}]
                       sut/scheme-base-env
                       (sut/symtable-for-env sut/scheme-base-env))))
  (t/is (= [#{0 1}]
           (sut/nearest ['x #{0 1 2}]
                        [#{0} #{0 1} #{0 3}]))))

(t/deftest expand-test
  (t/testing "unbound symbol"
    (t/is (thrown? Exception (sut/expand 'x))))
  (t/testing "identity fn"
    (t/is (= '(lambda (x) x)
             (sut/expand '(λ (x) x))))))