move url filter functionality to service ProductFiltersService

spec/javascripts/unit/admin/services/product_filters_spec.js.coffee

@@ -0,0 +1,68 @@
+describe "ProductFiltersService service", ->
+  ProductFiltersService = null
+
+  beforeEach ->
+    module "ofn.admin"
+
+  beforeEach inject (_ProductFiltersService_) ->
+    ProductFiltersService = _ProductFiltersService_
+
+  describe "loadFromUrl", ->
+    it "should return a hash with value populated for filters existing in parameter", ->
+      producerFilter = 2
+      query = 'fruit'
+
+      filters = ProductFiltersService.loadFromUrl(producerFilter: producerFilter, query: query)
+
+      expect(filters.producerFilter).toBe producerFilter
+      expect(filters.query).toBe query
+
+    it "should return a hash with empty value for filters missing from parameter", ->
+      filters = ProductFiltersService.loadFromUrl({})
+
+      expect(filters.producerFilter).toBe ""
+      expect(filters.query).toBe ""
+      expect(filters.categoryFilter).toBe ""
+      expect(filters.sorting).toBe ""
+      expect(filters.importDateFilter).toBe ""
+
+  describe "generate", ->
+    it 'should filter given hash with productFilters', ->
+      producerFilter = 2
+      query = 'fruit'
+
+      filters = ProductFiltersService.generate(
+        producerFilter: producerFilter, query: query, otherParam: 'otherParam'
+      )
+
+      expect(filters.producerFilter).toBe producerFilter
+      expect(filters.query).toBe query
+      expect(filters.otherParam).toBe undefined
+
+  describe "buildUrl", ->
+    it 'should return a url adding filters to the baseUrl', inject ($httpParamSerializer) ->
+      query = 'lala'
+      producerFilter = 2
+      categoryFilter = 5
+      sorting = 'name desc'
+      importDateFilter = '2020-06-08'
+      filters = {
+        producerFilter: producerFilter
+        categoryFilter: categoryFilter
+        query: query
+        sorting: sorting
+        importDateFilter: importDateFilter
+      }
+      baseUrl = "openfoodnetwork.org.au"
+
+      url = ProductFiltersService.buildUrl(baseUrl, filters)
+
+      expectedFilters = $httpParamSerializer(filters)
+      expect(url).toBe("#{baseUrl}?#{expectedFilters}")
+
+    it 'should return baseUrl if filters are empty', ->
+      baseUrl = "openfoodnetwork.org.au"
+
+      url = ProductFiltersService.buildUrl(baseUrl, {})
+      expect(url).toBe baseUrl
+