Implement explanation of collOf

mrijk · May 24, 2017 · 7cc1ca9 · 7cc1ca9
1 parent 2c465f8
commit 7cc1ca9
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Showing 5 changed files with 71 additions and 23 deletions.
diff --git a/lib/collOf.js b/lib/collOf.js
@@ -4,6 +4,7 @@ const {gen: tcg} = require('testcheck');
 
 const {invalidString} = require('./conform');
 const {spec: specize} = require('./def');
+const explainData = require('./explainData');
 const {gen} = require('./gen');
 const {checkCount} = require('./util/helper');
 const isValid = require('./isValid');
@@ -13,10 +14,10 @@ const describe = require('./util/describe');
 function collOf(predicate, options = {}) {
     const {kind = () => true, distinct = false, into} = options;
     const uniq = value => !distinct || isUnique(value);
+    const spec = specize(predicate);
 
     return {
         conform: value => {
-            const spec = specize(predicate);
             const result = kind(value) && uniq(value) && checkCount(value, options)
                   && _.every(value, v => isValid(spec, v));
             return result ? transform(value, into) : invalidString;
@@ -26,10 +27,22 @@ function collOf(predicate, options = {}) {
             const count = options.count || 10;
             return tcg.array(gen(predicate), {size: count});
         }),
-        describe: () => [collOf.name, ...describe([predicate]), ...describe(_.flatten(_.toPairs(options)))]
+        describe: () => [collOf.name, ...describe([predicate]), ...describe(_.flatten(_.toPairs(options)))],
+        explain: function*(values, {via}) {
+            yield* explainInvalid(values, predicate, via);
+        }
     };
 }
 
+function* explainInvalid([v, ...rest], predicate, via, index = 0) {
+    if (v) {
+        if (!isValid(predicate, v)) {
+            yield explainData(predicate, v, {via, in: [index]}).problems[0];
+        }      
+        yield* explainInvalid(rest, predicate, via, ++index);
+    }
+}
+
 function isUnique(value) {
     return _.uniq(value).length === value.length;
 }

diff --git a/lib/def.js b/lib/def.js
@@ -20,9 +20,9 @@ function createArraySpec(predicate) {
     return {
         conform: (value, unwrap = false) => conform(value, unwrap, _.partial(_.includes, predicate)),
         describe: () => predicate,
-        explain: function*(value) {
+        explain: function*(value, options) {
             if (!_.includes(predicate, value)) {
-                yield getExplanation(value);
+                yield getExplanation(value, options);
             }
         },
         gen: () => tcg.null.then(() => tcg.return(_.sample(predicate)))
@@ -43,13 +43,13 @@ function createFunctionSpec(predicate, gen) {
     };
 }
 
-function getExplanation(value, {path, pred = unknownString, via}) {
+function getExplanation(value, {path, pred = unknownString, via, in:_in = []}) {
     return {
         path,
         pred,
         val: value,
         via,
-        'in': []
+        'in': _in
     };
 }
 

diff --git a/lib/explainData.js b/lib/explainData.js
@@ -3,12 +3,12 @@ const _ = require('lodash');
 const {spec: specize} = require('./def');
 const {isString} = require('./utils');
 
-function explainData(spec, value, {path =  [], via = []} = {}) {
+function explainData(spec, value, {path =  [], via = [], in:_in = []} = {}) {
     const lookup = specize(spec);
     if (lookup) {
         const name = specName(spec);
         const viaOut = _.isUndefined(name) ? via : [name, ...via];
-        const problems = [...lookup.explain(value, {path, pred: name, via: viaOut})];
+        const problems = [...lookup.explain(value, {path, pred: name, via: viaOut, in: _in})];
         return _.isEmpty(problems) ? null : {problems};
     } else {
         throw new Error(`Unable to resolve spec ${spec}`);

diff --git a/test/collOf.js b/test/collOf.js
@@ -11,25 +11,48 @@ describe('Test the collOf function', () => {
         s.def('::vnum3', s.collOf(isNumber, {kind: isVector, count: 3, distinct: true}));
     });
 
-    it('should return a spec for a collection', () => {
-        expect(s.isValid('::vnum3', [1, 2, 3])).to.be.true;
+    describe('should handle valid input', () => {
+        it('should return a spec for a collection', () => {
+            expect(s.isValid('::vnum3', [1, 2, 3])).to.be.true;
+        });
+
+        it('explainData should return null', () => {
+            expect(s.explainData('::vnum3', [1, 2, 3])).to.be.null;
+        });
     });
 
-    it('should fail on invalid type (not a vector)', () => {
-        expect(s.isValid('::vnum3', {x: 1, y: 2, z: 3})).to.be.false;
+    describe('should reject invalid input', () => {
+        it('should fail on invalid type (not a vector)', () => {
+            expect(s.isValid('::vnum3', {x: 1, y: 2, z: 3})).to.be.false;
+        });
+
+        it('should fail on non-distinct data', () => {
+            expect(s.isValid('::vnum3', [1, 1, 1])).to.be.false;
+        });
+
+        it('should fail on invalid data', () => {
+            expect(s.isValid('::vnum3', [1, 2, 'foo'])).to.be.false;
+        });
+
+        it('explainData should report about wrong type', () => {
+            expect(s.explainData('::vnum3', [1, 2, 'foo'])).to.eql({
+                problems: [
+                    {
+                        path: [],
+                        pred: 'isNumber',
+                        val: 'foo',
+                        via: ['::vnum3'],
+                        'in': [2]
+                    }
+                ]
+            });
+        });
+
+        it('should fail on invalid length', () => {
+            expect(s.isValid('::vnum3', [1, 2, 3, 4])).to.be.false;
+        });
     });
 
-    it('should fail on non-distinct data', () => {
-        expect(s.isValid('::vnum3', [1, 1, 1])).to.be.false;
-    });
-
-    it('should fail on invalid data', () => {
-        expect(s.isValid('::vnum3', [1, 2, 'foo'])).to.be.false;
-    });
-
-    it('should fail on invalid length', () => {
-        expect(s.isValid('::vnum3', [1, 2, 3, 4])).to.be.false;
-    });
 
     it('should conform to a valid value',  () => {
         expect(s.conform(s.collOf(isNumber), [5, 10, 2])).to.eql([5, 10, 2]);

diff --git a/test/explainData.js b/test/explainData.js
@@ -13,6 +13,18 @@ describe('Test the explainData function', () => {
         expect(s.explainData([1, 2], 2)).to.equal(null);
     });
 
+    it('should report a problem when the value is not in the array', () => {
+        expect(s.explainData([1, 2], 3)).to.eql({
+            problems: [{
+                path: [],
+                pred: unknownString,
+                val: 3,
+                via: [],
+                'in': []
+            }]            
+        });
+    });
+
     it('should return an object explaining why the spec fails', () => {
         expect(s.explainData(isString, 1)).to.eql({
             problems: [{