Sync strain tests (#1609)

* Update existing tests to match problem-specs

* Add missing tests

* Add `predicate` variables

* Add missing return types for some predicates

* Fix unused predicate parameters

Author: BNAndras

exercises/practice/strain/.meta/tests.toml

@@ -0,0 +1,52 @@
+# 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.
+
+[26af8c32-ba6a-4eb3-aa0a-ebd8f136e003]
+description = "keep on empty list returns empty list"
+
+[f535cb4d-e99b-472a-bd52-9fa0ffccf454]
+description = "keeps everything"
+
+[950b8e8e-f628-42a8-85e2-9b30f09cde38]
+description = "keeps nothing"
+
+[92694259-6e76-470c-af87-156bdf75018a]
+description = "keeps first and last"
+
+[938f7867-bfc7-449e-a21b-7b00cbb56994]
+description = "keeps neither first nor last"
+
+[8908e351-4437-4d2b-a0f7-770811e48816]
+description = "keeps strings"
+
+[2728036b-102a-4f1e-a3ef-eac6160d876a]
+description = "keeps lists"
+
+[ef16beb9-8d84-451a-996a-14e80607fce6]
+description = "discard on empty list returns empty list"
+
+[2f42f9bc-8e06-4afe-a222-051b5d8cd12a]
+description = "discards everything"
+
+[ca990fdd-08c2-4f95-aa50-e0f5e1d6802b]
+description = "discards nothing"
+
+[71595dae-d283-48ca-a52b-45fa96819d2f]
+description = "discards first and last"
+
+[ae141f79-f86d-4567-b407-919eaca0f3dd]
+description = "discards neither first nor last"
+
+[daf25b36-a59f-4f29-bcfe-302eb4e43609]
+description = "discards strings"
+
+[a38d03f9-95ad-4459-80d1-48e937e4acaf]
+description = "discards lists"

exercises/practice/strain/strain.test.ts

@@ -3,30 +3,35 @@ import { keep, discard } from './strain.ts'
 
 describe('strain', () => {
   it('keeps on empty array returns empty array', () => {
-    expect(keep<number>([], (e: number) => e < 10)).toEqual([])
+    const predicate = (_: number): boolean => true
+    expect(keep<number>([], predicate)).toEqual([])
   })
 
   xit('keeps everything', () => {
-    expect(keep<number>([1, 2, 3], (e: number) => e < 10)).toEqual([1, 2, 3])
+    const predicate = (_: number): boolean => true
+    expect(keep<number>([1, 3, 5], predicate)).toEqual([1, 3, 5])
+  })
+
+  xit('keeps nothing', () => {
+    const predicate = (_: number): boolean => false
+    expect(keep<number>([1, 3, 5], predicate)).toEqual([])
   })
 
   xit('keeps first and last', () => {
-    expect(keep<number>([1, 2, 3], (e: number) => e % 2 === 1)).toEqual([1, 3])
+    const predicate = (e: number): boolean => e % 2 === 1
+    expect(keep<number>([1, 2, 3], predicate)).toEqual([1, 3])
   })
 
   xit('keeps neither first nor last', () => {
-    expect(keep<number>([1, 2, 3, 4, 5], (e: number) => e % 2 === 0)).toEqual([
-      2, 4,
-    ])
+    const predicate = (e: number): boolean => e % 2 === 0
+    expect(keep<number>([1, 2, 3], predicate)).toEqual([2])
   })
 
   xit('keeps strings', () => {
-    const words = 'apple zebra banana zombies cherimoya zelot'.split(' ')
-    const result = keep<string>(
-      words,
-      (word: string) => word.indexOf('z') === 0
-    )
-    expect(result).toEqual('zebra zombies zelot'.split(' '))
+    const words = ['apple', 'zebra', 'banana', 'zombies', 'cherimoya', 'zealot']
+    const predicate = (word: string): boolean => word.indexOf('z') === 0
+    const result = keep<string>(words, predicate)
+    expect(result).toEqual(['zebra', 'zombies', 'zealot'])
   })
 
   xit('keeps arrays', () => {
@@ -39,7 +44,8 @@ describe('strain', () => {
       [2, 2, 1],
       [1, 2, 5],
     ]
-    const result = keep<number[]>(rows, (row: number[]) => row.indexOf(5) > -1)
+    const predicate = (row: number[]): boolean => row.indexOf(5) > -1
+    const result = keep<number[]>(rows, predicate)
     expect(result).toEqual([
       [5, 5, 5],
       [5, 1, 2],
@@ -49,29 +55,36 @@ describe('strain', () => {
   })
 
   xit('empty discard', () => {
-    expect(discard<number>([], (e: number) => e < 10)).toEqual([])
+    const predicate = (_: number): boolean => true
+    expect(discard<number>([], predicate)).toEqual([])
+  })
+
+  xit('discards everything', () => {
+    const predicate = (_: number): boolean => true
+    expect(discard<number>([1, 3, 5], predicate)).toEqual([])
   })
 
   it('discards nothing', () => {
-    expect(discard<number>([1, 2, 3], (e: number) => e > 10)).toEqual([1, 2, 3])
+    const predicate = (_: number): boolean => false
+    expect(discard<number>([1, 3, 5], predicate)).toEqual([1, 3, 5])
   })
 
   xit('discards first and last', () => {
-    expect(discard<number>([1, 2, 3], (e: number) => e % 2 === 1)).toEqual([2])
+    const predicate = (e: number): boolean => e % 2 === 1
+    expect(discard<number>([1, 2, 3], predicate)).toEqual([2])
   })
 
   xit('discards neither first nor last', () => {
-    const result = discard<number>([1, 2, 3, 4, 5], (e: number) => e % 2 === 0)
-    expect(result).toEqual([1, 3, 5])
+    const predicate = (e: number): boolean => e % 2 === 0
+    const result = discard<number>([1, 2, 3], predicate)
+    expect(result).toEqual([1, 3])
   })
 
   xit('discards strings', () => {
-    const words = 'apple zebra banana zombies cherimoya zelot'.split(' ')
-    const result = discard<string>(
-      words,
-      (word: string) => word.indexOf('z') === 0
-    )
-    expect(result).toEqual('apple banana cherimoya'.split(' '))
+    const words = ['apple', 'zebra', 'banana', 'zombies', 'cherimoya', 'zealot']
+    const predicate = (word: string): boolean => word.indexOf('z') === 0
+    const result = discard<string>(words, predicate)
+    expect(result).toEqual(['apple', 'banana', 'cherimoya'])
   })
 
   xit('discards arrays', () => {
@@ -84,10 +97,9 @@ describe('strain', () => {
       [2, 2, 1],
       [1, 2, 5],
     ]
-    const result = discard<number[]>(
-      rows,
-      (row: number[]) => row.indexOf(5) > -1
-    )
+
+    const predicate = (row: number[]): boolean => row.indexOf(5) > -1
+    const result = discard<number[]>(rows, predicate)
     expect(result).toEqual([
       [1, 2, 3],
       [2, 1, 2],