spec/policy/url_rewriting: avoid testing internals of QueryParams

spec/policy/url_rewriting/url_rewriting_spec.lua

@@ -1,5 +1,16 @@
 local URLRewriting = require('apicast.policy.url_rewriting')
 
+-- Mock QueryParams module. In these tests we are only interested in checking
+-- that a QueryParams instance is called with the appropriate params. We do
+-- not want to check its internals.
+local QueryParams = require('apicast.policy.url_rewriting.query_params')
+local noop = function() end
+local mocked_query_params = { push = noop, set = noop, add = noop }
+QueryParams.new = function() return mocked_query_params end
+local spy_mocked_query_params_push
+local spy_mocked_query_params_set
+local spy_mocked_query_params_add
+
 describe('URL rewriting policy', function()
   describe('.rewrite', function()
     before_each(function()
@@ -11,6 +22,10 @@ describe('URL rewriting policy', function()
 
       stub(ngx.req, 'get_uri_args', function() return {} end)
       stub(ngx.req, 'set_uri_args')
+
+      spy_mocked_query_params_push = spy.on(mocked_query_params, 'push')
+      spy_mocked_query_params_set = spy.on(mocked_query_params, 'set')
+      spy_mocked_query_params_add = spy.on(mocked_query_params, 'add')
     end)
 
     it('can rewrite URLs using sub', function()
@@ -83,54 +98,45 @@ describe('URL rewriting policy', function()
     end)
 
     it('can apply the "push" operation to args in the query', function()
-      stub(ngx.req, 'get_uri_args', function()
-        return { an_arg = '1'}
-      end)
-
       local config_to_add_args = {
         query_args_commands = {
-          { op = 'push', arg = 'an_arg', value = '2' }
+          { op = 'push', arg = 'an_arg', value = '1' }
         }
       }
       local url_rewriting = URLRewriting.new(config_to_add_args)
 
       url_rewriting:rewrite()
 
-      assert.stub(ngx.req.set_uri_args).was_called_with({ an_arg = { '1', '2' } })
+      assert.spy(spy_mocked_query_params_push).was_called_with(
+        mocked_query_params, 'an_arg', '1')
     end)
 
     it('can apply the "set" operation to args in the query', function()
-      stub(ngx.req, 'get_uri_args', function()
-        return { an_arg = 'original_value'}
-      end)
-
       local config_to_replace_args = {
         query_args_commands = {
-          { op = 'set', arg = 'an_arg', value = 'new_val' }
+          { op = 'set', arg = 'an_arg', value = '1' }
         }
       }
       local url_rewriting = URLRewriting.new(config_to_replace_args)
 
       url_rewriting:rewrite()
 
-      assert.stub(ngx.req.set_uri_args).was_called_with({ an_arg = 'new_val' })
+      assert.spy(spy_mocked_query_params_set).was_called_with(
+        mocked_query_params, 'an_arg', '1')
     end)
 
     it('can apply the "add" operation to args in the query', function()
-      stub(ngx.req, 'get_uri_args', function()
-        return { an_arg = '1'}
-      end)
-
       local config_to_add_args = {
         query_args_commands = {
-          { op = 'add', arg = 'an_arg', value = '2' }
+          { op = 'add', arg = 'an_arg', value = '1' }
         }
       }
       local url_rewriting = URLRewriting.new(config_to_add_args)
 
       url_rewriting:rewrite()
 
-      assert.stub(ngx.req.set_uri_args).was_called_with({ an_arg = { '1', '2' } })
+      assert.spy(spy_mocked_query_params_add).was_called_with(
+        mocked_query_params, 'an_arg', '1')
     end)
 
     it('supports liquid templates when pushing query args', function()
@@ -151,8 +157,8 @@ describe('URL rewriting policy', function()
 
       url_rewriting:rewrite(context)
 
-      assert.stub(ngx.req.set_uri_args).was_called_with(
-        { an_arg = context.var_in_context })
+      assert.spy(spy_mocked_query_params_push).was_called_with(
+        mocked_query_params, 'an_arg', context.var_in_context)
     end)
 
     it('supports liquid templates when setting query args', function()
@@ -173,11 +179,11 @@ describe('URL rewriting policy', function()
 
       url_rewriting:rewrite(context)
 
-      assert.stub(ngx.req.set_uri_args).was_called_with(
-        { an_arg = context.var_in_context })
+      assert.spy(spy_mocked_query_params_set).was_called_with(
+        mocked_query_params, 'an_arg', context.var_in_context)
     end)
 
-    it('supports liquid templates when replacing query args', function()
+    it('supports liquid templates when adding query args', function()
       stub(ngx.req, 'get_uri_args', function()
         return { an_arg = 'original_value'}
       end)
@@ -199,8 +205,8 @@ describe('URL rewriting policy', function()
 
       url_rewriting:rewrite(context)
 
-      assert.stub(ngx.req.set_uri_args).was_called_with(
-        { an_arg = { 'original_value', context.var_in_context } })
+      assert.spy(spy_mocked_query_params_add).was_called_with(
+        mocked_query_params, 'an_arg', context.var_in_context)
     end)
   end)
 end)