Route: Add `#calculate_costs!` to populate `#costs` with `WayCost`s

This new method will launch a worker that takes the route's `StopArea`s,
converts them to `WayCost`s, sends them to the TomTom API to calculate
distance and time costs, and saves those costs to the route's `costs`
field.

Refs #6095

1 files changed, 31 insertions, 0 deletions

diff --git a/spec/services/route_way_cost_calculator_spec.rb b/spec/services/route_way_cost_calculator_spec.rb
new file mode 100644
index 000000000..d5358fcf6
--- /dev/null
+++ b/spec/services/route_way_cost_calculator_spec.rb
@@ -0,0 +1,31 @@
+RSpec.describe RouteWayCostCalculator do
+  describe "#calculate!" do
+    it "calculates and stores WayCosts in the given route's #cost field" do
+      route = create(:route)
+
+      # Fake the request to the TomTom API, but don't actually send the right
+      # things in the request or response. This is just to fake the request so
+      # we don't actually call their API in tests. The test doesn't test
+      # anything given in the response.
+      stub_request(:post, "https://api.tomtom.com/routing/1/batch/json?key")
+        .with(
+          headers: {
+            'Accept'=>'*/*',
+            'Accept-Encoding'=>'gzip;q=1.0,deflate;q=0.6,identity;q=0.3',
+            'Content-Type'=>'application/json',
+            'User-Agent'=>'Faraday v0.9.2'
+          }
+        )
+        .to_return(
+          status: 200,
+          body: "{\"formatVersion\":\"0.0.1\",\"batchItems\":[{\"statusCode\":200,\"response\":{\"routes\":[{\"summary\":{\"lengthInMeters\":117947,\"travelTimeInSeconds\":7969,\"trafficDelayInSeconds\":0,\"departureTime\":\"2018-03-12T12:32:26+01:00\",\"arrivalTime\":\"2018-03-12T14:45:14+01:00\"}}]}}]}",
+          headers: {}
+        )
+
+      RouteWayCostCalculator.new(route).calculate!
+
+      expect(route.costs).not_to be_nil
+      expect { JSON.parse(JSON.dump(route.costs)) }.not_to raise_error
+    end
+  end
+end