Fixed two-bucket solution & errant tests (#905) (#1396)

Author: qianzhong516

exercises/practice/two-bucket/.meta/proof.ci.js

@@ -95,11 +95,29 @@ export class TwoBucket {
     return mvCount;
   }
 
+  gcd(a, b) {
+    // greatest common divisor
+    if (!b) {
+      return a;
+    }
+    return this.gcd(b, a % b);
+  }
+
   moves() {
-    let j = 0;
     // j will be running val of bucket one, k = running val of bucket two
+    let j = 0;
     let k = 0;
 
+    // if the goal is not a multiple of the gcd of bucket one and bucket two,
+    // or the goal is bigger than both buckets,
+    // the solution will be impossible.
+    if (
+      this.z % this.gcd(this.x, this.y) !== 0 ||
+      (this.z > this.x && this.z > this.y)
+    ) {
+      throw new Error('Cannot reach the goal.');
+    }
+
     if (this.starter === 'one') {
       j = this.x;
     } else {

exercises/practice/two-bucket/.meta/tests.toml

@@ -1,6 +1,13 @@
-# This is an auto-generated file. Regular comments will be removed when this
-# file is regenerated. Regenerating will not touch any manually added keys,
-# so comments can be added in a "comment" key.
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
 
 [a6f2b4ba-065f-4dca-b6f0-e3eee51cb661]
 description = "Measure using bucket one of size 3 and bucket two of size 5 - start with bucket one"

exercises/practice/two-bucket/two-bucket.spec.js

@@ -59,26 +59,34 @@ describe('TwoBucket', () => {
   });
 
   describe('Measure using bucket one of size 2 and bucket two of size 3', () => {
-    test.skip('start with bucket one and end with bucket two', () => {
+    xtest('start with bucket one and end with bucket two', () => {
       const twoBucket = new TwoBucket(2, 3, 3, 'one');
-      expect(twoBucket.moves()).toEqual(2);
+      expect(twoBucket.moves()).toEqual(4);
       expect(twoBucket.goalBucket).toEqual('two');
-      expect(twoBucket.otherBucket).toEqual(2);
+      expect(twoBucket.otherBucket).toEqual(1);
     });
   });
 
   describe('Reachability', () => {
     const buckOne = 6;
     const buckTwo = 15;
-    const starterBuck = 'one';
 
-    test.skip('Not possible to reach the goal', () => {
+    xtest('Not possible to reach the goal, start with bucket one', () => {
+      const starterBuck = 'one';
+      const goal = 5;
+      const twoBucket = new TwoBucket(buckOne, buckTwo, goal, starterBuck);
+      expect(() => twoBucket.moves()).toThrow();
+    });
+
+    xtest('Not possible to reach the goal, start with bucket two', () => {
+      const starterBuck = 'two';
       const goal = 5;
       const twoBucket = new TwoBucket(buckOne, buckTwo, goal, starterBuck);
       expect(() => twoBucket.moves()).toThrow();
     });
 
     xtest('With the same buckets but a different goal, then it is possible', () => {
+      const starterBuck = 'one';
       const goal = 9;
       const twoBucket = new TwoBucket(buckOne, buckTwo, goal, starterBuck);
       expect(twoBucket.moves()).toEqual(10);
@@ -88,7 +96,7 @@ describe('TwoBucket', () => {
   });
 
   describe('Goal larger than both buckets', () => {
-    test.skip('Is impossible', () => {
+    xtest('Is impossible', () => {
       const twoBucket = new TwoBucket(5, 7, 8, 'one');
       expect(() => twoBucket.moves()).toThrow();
     });