fix tests

src/algebra/option.js

@@ -23,6 +23,11 @@ export class Some extends Algebra(Monoid, Monad, Foldable) {
     return new Some(value)
   }
 
+  equals(other) {
+    return other instanceof Some &&
+      other.chain(v => v === this.#value)
+  }
+
   /**
    * @template R
    * @param {Morphism<T, R>} f
@@ -67,6 +72,10 @@ export class Some extends Algebra(Monoid, Monad, Foldable) {
 
 /** @template T */
 export class None extends Algebra(Monoid, Monad, Foldable) {
+  equals(other) {
+    return other === none
+  }
+
   /**
    * @template R
    * @param {Morphism<T, R>} _f

src/algebra/result.js

@@ -19,6 +19,11 @@ export class Ok extends Algebra(Monad, Foldable) {
     this.#value = value
   }
 
+  equals(other) {
+    return other instanceof Ok &&
+      other.chain(v => v === this.#value)
+  }
+
   /** @returns {this is Ok<T, E>} */
   isOk() { return true }
 
@@ -92,6 +97,11 @@ export class Err extends Algebra(Functor, Monad) {
     this.#value = value
   }
 
+  equals(other) {
+    return other instanceof Err &&
+      other.chain(v => v === this.#value)
+  }
+
   /** @returns {this is Ok<T, E>} */
   isOk() { return false }
 

tests/units/monad.js

@@ -1,16 +1,16 @@
-import { it, assertEq } from 'folktest'
-import { Ok, Err, Some, None } from '../../src/index.js'
+import { it, assert } from 'folktest'
+import { Option, Result } from '../../src/index.js'
 
 const leftIdentity = (M, a, f) => {
-  assertEq(M(a).bind(f), f(a))
+  assert(M(a).chain(f).equals(f(a)))
 }
 
 const rightIdentity = (M, m) => {
-  assertEq(m.bind(M), m)
+  assert(m.chain(M).equals(m))
 }
 
 const associativity = (m, f, g) => {
-  assertEq(m.bind(f).bind(g), m.bind(x => f(x).bind(g)))
+  assert(m.chain(f).chain(g).equals(m.chain(x => f(x).chain(g))))
 }
 
 export const prove = (M, m, a, f, g) => {
@@ -21,13 +21,15 @@ export const prove = (M, m, a, f, g) => {
 
 export const Tests = [
   it('should adhere to monadic laws', () => {
-    [Ok, Err, Some, None].forEach(ctr => {
+    [Option, Result].forEach(F => {
+      const Ctr = F.of
+
       prove(
-        ctr,
-        ctr(1),
+        Ctr,
+        Ctr(1),
         1,
-        x => ctr(x + 1),
-        x => ctr(x * 2)
+        x => Ctr(x + 1),
+        x => Ctr(x * 2)
       )
     })
   })