DataValidator: Always clear store state

In practice, not clearing the store and allowing it to use previous
state has the effect of instantly "fixing" failures if there happens
to be more than one validation call.

This was a log of debugging for a one-line change.

* src/validate/DataValidator.js (_populateStore): Always clear store.
* test/validate/DataValidatorTest.js: Add test.

DEV-2299

2 files changed, 41 insertions, 1 deletions

diff --git a/src/validate/DataValidator.js b/src/validate/DataValidator.js
index 12e663f..3690ac5 100644
--- a/src/validate/DataValidator.js
+++ b/src/validate/DataValidator.js
@@ -193,7 +193,8 @@ module.exports = Class( 'DataValidator',
     {
         if ( data === undefined )
         {
-            return Promise.resolve( [] );
+            // it's important that we don't re-use previous state
+            return store.clear().then( [] );
         }
 
         const mapf = ( subkey !== undefined )
diff --git a/test/validate/DataValidatorTest.js b/test/validate/DataValidatorTest.js
index b31a93e..e2364d3 100644
--- a/test/validate/DataValidatorTest.js
+++ b/test/validate/DataValidatorTest.js
@@ -212,6 +212,45 @@ describe( 'DataValidator', () =>
                     .validate( {} )
             ).to.eventually.be.rejectedWith( expected_e );
         } );
+
+
+        [
+            [],
+            [ {} ],
+            [ undefined ],
+            [ undefined, {} ],
+            [ undefined, undefined ],
+            [ {}, undefined ],
+        ].forEach( args => it( 'does not re-use previous store state', () =>
+        {
+            const bvalidator  = createMockBucketValidator();
+            const vmonitor    = ValidStateMonitor();
+            const dep_factory = createMockDependencyFactory();
+
+            const stores = {
+                store: MemoryStore(),
+                bstore: sinon.createStubInstance( MemoryStore ),
+                cstore: sinon.createStubInstance( MemoryStore ),
+            };
+
+            const { bstore, cstore } = stores;
+
+            const cleared = which =>
+            {
+                cleared[ which ] = true;
+                return Promise.resolve();
+            };
+
+            bstore.clear = () => cleared( 'b' );
+            cstore.clear = () => cleared( 'c' );
+
+            const sut = Sut( bvalidator, vmonitor, dep_factory, () => stores );
+
+            return sut.validate.apply( sut, args )
+                .then( () =>
+                    expect( cleared.b && cleared.c ).to.be.true
+                );
+        } ) );
     } );