Restructure project

We previously didn't really had any structure in our project apart
from creating a new folder for each package in our project root.
Now that we have accumulated some packages, we use the well-known
Golang project layout in order to clearly communicate our intent
with packages. See https://github.com/golang-standards/project-layout

internal/runner/storage_test.go

@@ -0,0 +1,103 @@
+package runner
+
+import (
+	"github.com/stretchr/testify/suite"
+	"gitlab.hpi.de/codeocean/codemoon/poseidon/pkg/dto"
+	"gitlab.hpi.de/codeocean/codemoon/poseidon/tests"
+	"testing"
+)
+
+func TestRunnerPoolTestSuite(t *testing.T) {
+	suite.Run(t, new(RunnerPoolTestSuite))
+}
+
+type RunnerPoolTestSuite struct {
+	suite.Suite
+	runnerStorage *localRunnerStorage
+	runner        Runner
+}
+
+func (s *RunnerPoolTestSuite) SetupTest() {
+	s.runnerStorage = NewLocalRunnerStorage()
+	s.runner = NewRunner(tests.DefaultRunnerID, nil)
+	s.runner.Add(tests.DefaultExecutionID, &dto.ExecutionRequest{Command: "true"})
+}
+
+func (s *RunnerPoolTestSuite) TestAddedRunnerCanBeRetrieved() {
+	s.runnerStorage.Add(s.runner)
+	retrievedRunner, ok := s.runnerStorage.Get(s.runner.ID())
+	s.True(ok, "A saved runner should be retrievable")
+	s.Equal(s.runner, retrievedRunner)
+}
+
+func (s *RunnerPoolTestSuite) TestRunnerWithSameIdOverwritesOldOne() {
+	otherRunnerWithSameID := NewRunner(s.runner.ID(), nil)
+	// assure runner is actually different
+	s.NotEqual(s.runner, otherRunnerWithSameID)
+
+	s.runnerStorage.Add(s.runner)
+	s.runnerStorage.Add(otherRunnerWithSameID)
+	retrievedRunner, _ := s.runnerStorage.Get(s.runner.ID())
+	s.NotEqual(s.runner, retrievedRunner)
+	s.Equal(otherRunnerWithSameID, retrievedRunner)
+}
+
+func (s *RunnerPoolTestSuite) TestDeletedRunnersAreNotAccessible() {
+	s.runnerStorage.Add(s.runner)
+	s.runnerStorage.Delete(s.runner.ID())
+	retrievedRunner, ok := s.runnerStorage.Get(s.runner.ID())
+	s.Nil(retrievedRunner)
+	s.False(ok, "A deleted runner should not be accessible")
+}
+
+func (s *RunnerPoolTestSuite) TestSampleReturnsRunnerWhenOneIsAvailable() {
+	s.runnerStorage.Add(s.runner)
+	sampledRunner, ok := s.runnerStorage.Sample()
+	s.NotNil(sampledRunner)
+	s.True(ok)
+}
+
+func (s *RunnerPoolTestSuite) TestSampleReturnsFalseWhenNoneIsAvailable() {
+	sampledRunner, ok := s.runnerStorage.Sample()
+	s.Nil(sampledRunner)
+	s.False(ok)
+}
+
+func (s *RunnerPoolTestSuite) TestSampleRemovesRunnerFromPool() {
+	s.runnerStorage.Add(s.runner)
+	sampledRunner, _ := s.runnerStorage.Sample()
+	_, ok := s.runnerStorage.Get(sampledRunner.ID())
+	s.False(ok)
+}
+
+func (s *RunnerPoolTestSuite) TestLenOfEmptyPoolIsZero() {
+	s.Equal(0, s.runnerStorage.Length())
+}
+
+func (s *RunnerPoolTestSuite) TestLenChangesOnStoreContentChange() {
+	s.Run("len increases when runner is added", func() {
+		s.runnerStorage.Add(s.runner)
+		s.Equal(1, s.runnerStorage.Length())
+	})
+
+	s.Run("len does not increase when runner with same id is added", func() {
+		s.runnerStorage.Add(s.runner)
+		s.Equal(1, s.runnerStorage.Length())
+	})
+
+	s.Run("len increases again when different runner is added", func() {
+		anotherRunner := NewRunner(tests.AnotherRunnerID, nil)
+		s.runnerStorage.Add(anotherRunner)
+		s.Equal(2, s.runnerStorage.Length())
+	})
+
+	s.Run("len decreases when runner is deleted", func() {
+		s.runnerStorage.Delete(s.runner.ID())
+		s.Equal(1, s.runnerStorage.Length())
+	})
+
+	s.Run("len decreases when runner is sampled", func() {
+		_, _ = s.runnerStorage.Sample()
+		s.Equal(0, s.runnerStorage.Length())
+	})
+}