1 files changed, 137 insertions, 0 deletions
diff --git a/spec/services/retry_service_spec.rb b/spec/services/retry_service_spec.rb
new file mode 100644
index 000000000..bb3416373
--- /dev/null
+++ b/spec/services/retry_service_spec.rb
@@ -0,0 +1,137 @@
+RSpec.describe RetryService do
+  subject { described_class.new delays: [2, 3], rescue_from: [NameError, ArgumentError] }
+
+  context 'no retry necessary' do
+    before do
+      expect( subject ).not_to receive(:sleep)
+    end
+
+    it 'returns an ok result' do
+      expect( subject.execute { 42 } ).to eq(Result.ok(42))
+    end
+    it 'does not fail on nil' do
+      expect( subject.execute { nil } ).to eq(Result.ok(nil))
+    end
+
+    it 'fails wihout retries if raising un unregistered exception' do
+      expect{ subject.execute{ raise KeyError } }.to raise_error(KeyError)
+    end
+
+  end
+
+  context 'all retries fail' do
+    before do
+      expect( subject ).to receive(:sleep).with(2)
+      expect( subject ).to receive(:sleep).with(3)
+    end
+    it 'fails after raising a registered exception n times' do
+      result = subject.execute{ raise ArgumentError }
+      expect( result.status ).to eq(:error)
+      expect( result.value ).to be_kind_of(ArgumentError)
+    end
+    it 'fails with an explicit try again (automatically registered exception)'  do
+      result = subject.execute{ raise RetryService::Retry }
+      expect( result.status ).to eq(:error)
+      expect( result.value ).to be_kind_of(RetryService::Retry)
+    end
+  end
+
+  context "if at first you don't succeed" do
+    before do
+      @count = 0
+      expect( subject ).to receive(:sleep).with(2)
+    end
+
+    it 'succeeds the second time' do
+      expect( subject.execute{ succeed_later(ArgumentError){ 42 } } ).to eq(Result.ok(42))
+    end
+
+    it 'succeeds the second time with try again (automatically registered exception)' do
+      expect( subject.execute{ succeed_later(RetryService::Retry){ 42 } } ).to eq(Result.ok(42))
+    end
+  end
+
+  context 'last chance' do
+    before do
+      @count = 0
+      expect( subject ).to receive(:sleep).with(2)
+      expect( subject ).to receive(:sleep).with(3)
+    end
+    it 'succeeds the third time with try again (automatically registered exception)' do
+      result = subject.execute{ succeed_later(RetryService::Retry, count: 2){ 42 } }  
+      expect( result ).to eq( Result.ok(42) )
+    end
+  end
+
+  context 'failure callback once' do 
+    subject do 
+      described_class.new delays: [2, 3], rescue_from: [NameError, ArgumentError] do |reason, count|
+        @reason=reason
+        @callback_count=count
+        @failures += 1 
+      end
+    end
+
+    before do
+      @failures = 0
+      @count    = 0
+      expect( subject ).to receive(:sleep).with(2)
+    end
+
+    it 'succeeds the second time and calls the failure_callback once' do
+      subject.execute{ succeed_later(RetryService::Retry){ 42 } }
+      expect( @failures ).to eq(1)
+    end
+    it '... and the failure is passed into the callback' do
+      subject.execute{ succeed_later(RetryService::Retry){ 42 } }
+      expect( @reason ).to be_a(RetryService::Retry)
+      expect( @callback_count ).to eq(1)
+    end
+  end
+
+  context 'failure callback twice' do
+    subject do 
+      described_class.new delays: [2, 3], rescue_from: [NameError, ArgumentError] do |_reason, _count|
+        @failures += 1 
+      end
+    end
+
+    before do
+      @failures = 0
+      @count    = 0
+      expect( subject ).to receive(:sleep).with(2)
+      expect( subject ).to receive(:sleep).with(3)
+    end
+
+    it 'succeeds the third time and calls the failure_callback twice' do
+      subject.execute{ succeed_later(NameError, count: 2){ 42 } }
+      expect( @failures ).to eq(2)
+    end
+  end
+
+  context 'failure callback in constructor' do
+    subject do
+      described_class.new(delays: [1, 2], &method(:add2failures))
+    end
+    before do
+      @failures = []
+      @count    = 0
+      expect( subject ).to receive(:sleep).with(1)
+      expect( subject ).to receive(:sleep).with(2)
+    end
+    it 'succeeds the second time and calls the failure_callback once' do
+      subject.execute{ succeed_later(RetryService::Retry, count: 2){ 42 } }
+      expect( @failures ).to eq([1,2])
+    end
+  end
+
+  def add2failures( e, c)
+    @failures << c 
+  end
+
+  def succeed_later error, count: 1, &blk
+    return blk.() unless @count < count
+    @count += 1
+    raise error, 'error'
+  end
+end