Move `TomTom::Matrix::RemoteError` to`TomTom::Errors::MatrixRemoteError`6884-tomtom-matrix--handle-error-when-response-doesn,t-inclu

I previously tried to correct a circular dependency problem in
a057276129b1f62b811743db3b8f867a05241ed3, but that didn't fix it (it was
intermittent, and came back).

After some wrangling, I've now deduced with some confidence that the
problem comes from `RouteWayCostCalculator`, which used
`TomTom::Matrix::RemoteError`. From the way it looks, this seems to mess
up the Rails autoloader since `tom_tom.rb` will try to load the `Matrix`
class from the `TomTom.matrix` call above. Or something.

In an attempt to fix the circular dependency error for real this time,
move the error class to a completely separate module from `Matrix`, and
refer to this when we need to use the error class.

Refs #6884

6 files changed, 19 insertions, 14 deletions

diff --git a/app/services/route_way_cost_calculator.rb b/app/services/route_way_cost_calculator.rb
index 58f9ad1d0..ca47a6772 100644
--- a/app/services/route_way_cost_calculator.rb
+++ b/app/services/route_way_cost_calculator.rb
@@ -8,7 +8,7 @@ class RouteWayCostCalculator
     way_costs = TomTom.matrix(way_costs)
     way_costs = WayCostCollectionJSONSerializer.dump(way_costs)
     @route.update(costs: way_costs)
-  rescue TomTom::Matrix::RemoteError => e
+  rescue TomTom::Errors::MatrixRemoteError => e
     Rails.logger.error "TomTom::Matrix server error: #{e}"
   end
 end
diff --git a/lib/tom_tom/errors.rb b/lib/tom_tom/errors.rb
new file mode 100644
index 000000000..da3f2239c
--- /dev/null
+++ b/lib/tom_tom/errors.rb
@@ -0,0 +1,4 @@
+module TomTom
+  module Errors
+  end
+end
diff --git a/lib/tom_tom/errors/matrix_remote_error.rb b/lib/tom_tom/errors/matrix_remote_error.rb
new file mode 100644
index 000000000..b13767847
--- /dev/null
+++ b/lib/tom_tom/errors/matrix_remote_error.rb
@@ -0,0 +1,5 @@
+module TomTom
+  module Errors
+    class MatrixRemoteError < RuntimeError; end
+  end
+end
diff --git a/lib/tom_tom/matrix.rb b/lib/tom_tom/matrix.rb
index d0b476d84..96518f7cf 100644
--- a/lib/tom_tom/matrix.rb
+++ b/lib/tom_tom/matrix.rb
@@ -6,8 +6,8 @@ module TomTom
 
     # Exceptions:
     #
-    # * This raises a `TomTom::Matrix::RemoteError` when the API responds with
-    #   an error.
+    # * This raises a `TomTom::Errors::MatrixRemoteError` when the API responds
+    #   with an error.
     def matrix(way_costs)
       points_with_ids = points_from_way_costs(way_costs)
       points = points_as_params(points_with_ids)
@@ -84,13 +84,14 @@ module TomTom
 
     def check_for_error_response(response)
       if response.status != 200
-        raise RemoteError, "status: #{response.status}, body: #{response.body}"
+        raise TomTom::Errors::MatrixRemoteError,
+          "status: #{response.status}, body: #{response.body}"
       end
 
       json = JSON.parse(response.body)
 
       if json.has_key?('error')
-        raise RemoteError,
+        raise TomTom::Errors::MatrixRemoteError,
           "status: #{response.status}, message: #{json['error']['description']}"
       end
     end
diff --git a/lib/tom_tom/matrix/remote_error.rb b/lib/tom_tom/matrix/remote_error.rb
deleted file mode 100644
index a5a7b3cdb..000000000
--- a/lib/tom_tom/matrix/remote_error.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-module TomTom
-  class Matrix
-    class RemoteError < RuntimeError; end
-  end
-end
diff --git a/spec/lib/tom_tom/matrix_spec.rb b/spec/lib/tom_tom/matrix_spec.rb
index 6564b82fd..f914cf7ff 100644
--- a/spec/lib/tom_tom/matrix_spec.rb
+++ b/spec/lib/tom_tom/matrix_spec.rb
@@ -150,7 +150,7 @@ RSpec.describe TomTom::Matrix do
   end
 
   describe "#check_for_error_response" do
-    it "raises a RemoteError when an 'error' key is present in the response" do
+    it "raises a MatrixRemoteError when an 'error' key is present in the response" do
       response = double(
         'response',
         status: 200,
@@ -165,12 +165,12 @@ RSpec.describe TomTom::Matrix do
       expect {
         matrix.check_for_error_response(response)
       }.to raise_error(
-        TomTom::Matrix::RemoteError,
+        TomTom::Errors::MatrixRemoteError,
         "status: #{response.status}, message: Output format: csv is unsupported."
       )
     end
 
-    it "raises a RemoteError when response status is not 200" do
+    it "raises a MatrixRemoteError when response status is not 200" do
       response = double(
         'response',
         status: 403,
@@ -180,7 +180,7 @@ RSpec.describe TomTom::Matrix do
       expect {
         matrix.check_for_error_response(response)
       }.to raise_error(
-        TomTom::Matrix::RemoteError,
+        TomTom::Errors::MatrixRemoteError,
         "status: #{response.status}, body: <h1>Developer Inactive</h1>"
       )
     end