diff --git a/tests/build-query.test.js b/tests/build-query.test.js
index aa92b0b..29e4d9c 100644
--- a/tests/build-query.test.js
+++ b/tests/build-query.test.js
@@ -5,7 +5,7 @@ const { buildQuery } = require('../src/build-query');
 describe('Build Query', () => {
   describe('when a valid config is passed into buildQuery', () => {
     const expectedQuery =
-      '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&filter[]=regulation(182%2C26)&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist';
+      '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&filter[]=regulation(182%2C26)&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist&filter[]=founded.year%3A2010';
 
     let result;
 
@@ -32,7 +32,7 @@ describe('Build Query', () => {
 
   describe('when a config is passed with invalid regulation fields', () => {
     const expectedQueryNoRegulationValues =
-      '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist';
+      '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist&filter[]=founded.year%3A2010';
 
     let result;
 
@@ -54,7 +54,7 @@ describe('Build Query', () => {
 
   describe('when a config is passed with a non-numeric regulation size', () => {
     const expectedQueryRegulationSizeNull =
-      '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&filter[]=regulation(null%2C26)&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist';
+      '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&filter[]=regulation(null%2C26)&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist&filter[]=founded.year%3A2010';
 
     let result;
 
@@ -77,7 +77,7 @@ describe('Build Query', () => {
 
   describe('when a config is passed with a non-numeric regulation age', () => {
     const expectedQueryRegulationAgeNull =
-    '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&filter[]=regulation(182%2Cnull)&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist';
+    '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&filter[]=regulation(182%2Cnull)&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist&filter[]=founded.year%3A2010';
 
     let result;
 
@@ -97,4 +97,24 @@ describe('Build Query', () => {
       expect(result).toEqual(expectedQueryRegulationAgeNull);
     });
   });
+
+  describe('when a config is passed with a non-numeric founded year', () => {
+    const expectedQueryFoundedYearNull =
+        '?page=98&itemsPerPage=99&search=soup&language=Gaelic&sort=Ascending&filter[]=regulation(182%2C26)&facet[]=facets&facet[]=exist&filter[]=filters&filter[]=exist';
+
+    let result;
+
+    const invalidRegulationFields = {
+      ...stubbedConfig,
+      founded: ['founders', 'exist'],
+    };
+
+    beforeEach(() => {
+      result = buildQuery(invalidRegulationFields);
+    });
+
+    it('returns founded year as null', () => {
+      expect(result).toEqual(expectedQueryFoundedYearNull);
+    });
+  });
 });
diff --git a/tests/test-data/stubbed-config.js b/tests/test-data/stubbed-config.js
index d403998..622329b 100644
--- a/tests/test-data/stubbed-config.js
+++ b/tests/test-data/stubbed-config.js
@@ -10,5 +10,5 @@ module.exports = {
   },
   facets: ['facets','exist'],
   filters: ['filters', 'exist'],
-  founded: ['founders', 'exist'],
+  founded: 2010,
 };