From 4df1d794c2493393d27784d482b6bb4c3dca5a3a Mon Sep 17 00:00:00 2001
From: Hakan Ensari <hakanensari@gmail.com>
Date: Fri, 21 Sep 2018 20:20:56 +0100
Subject: [PATCH] Don't return empty hashes

This happened when rebasing and converting to unavailable currencies. For instance, the following was returning empty hashes for dates prior to the release of the new Turkish Lira:

https://frankfurter.app/1999-01-01..?from=USD&to=TRY
---
 .rubocop.yml            |  4 +++-
 lib/quote/base.rb       | 21 ++++++++++-----------
 spec/quote/base_spec.rb | 29 ++++++++++++++++++++++++-----
 3 files changed, 37 insertions(+), 17 deletions(-)

diff --git a/.rubocop.yml b/.rubocop.yml
index f92cf18..46540ed 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -4,5 +4,7 @@ Documentation:
   Enabled: false
 Metrics/BlockLength:
   ExcludedMethods: ['describe', 'helpers']
+Metrics/AbcSize:
+  Max: 20.45
 Metrics/MethodLength:
-  Max: 11
+  Max: 13
diff --git a/lib/quote/base.rb b/lib/quote/base.rb
index cf78abf..d178369 100644
--- a/lib/quote/base.rb
+++ b/lib/quote/base.rb
@@ -64,19 +64,18 @@ module Quote
 
     def rebase_rates
       result.each do |date, rates|
-        add_euro(rates)
-
+        rates['EUR'] = amount if symbols.nil? || symbols.include?('EUR')
         divisor = rates.delete(base)
-        result[date] = rates.sort
-                            .map! do |iso_code, rate|
-                              [iso_code, round(amount * rate / divisor)]
-                            end
-                            .to_h
+        if rates.empty?
+          result.delete(date)
+        else
+          result[date] = rates.sort
+                              .map! do |iso_code, rate|
+                                [iso_code, round(amount * rate / divisor)]
+                              end
+                              .to_h
+        end
       end
     end
-
-    def add_euro(rates)
-      rates['EUR'] = amount if symbols.nil? || symbols.include?('EUR')
-    end
   end
 end
diff --git a/spec/quote/base_spec.rb b/spec/quote/base_spec.rb
index 249d7a0..039b1d2 100644
--- a/spec/quote/base_spec.rb
+++ b/spec/quote/base_spec.rb
@@ -34,11 +34,9 @@ module Quote
     end
 
     describe 'when given data' do
-      let(:klass) do
-        Class.new(Base) do
-          def fetch_data
-            []
-          end
+      before do
+        def quote.fetch_data
+          []
         end
       end
 
@@ -51,5 +49,26 @@ module Quote
         refute quote.perform
       end
     end
+
+    describe 'when rebasing and converting to an unavailable currency' do
+      let(:date) do
+        Date.today
+      end
+
+      let(:quote) do
+        klass.new(date: date, base: 'USD', symbols: ['FOO'])
+      end
+
+      before do
+        def quote.fetch_data
+          [{ date: date, iso_code: 'USD', rate: 1.2 }]
+        end
+      end
+
+      it 'finds nothing' do
+        quote.perform
+        quote.not_found?.must_equal true
+      end
+    end
   end
 end