#89: First implementation of longer result history

core/service-status.go

@@ -8,7 +8,7 @@ import (
 
 const (
 	// MaximumNumberOfResults is the maximum number of results that ServiceStatus.Results can have
-	MaximumNumberOfResults = 20
+	MaximumNumberOfResults = 100
 
 	// MaximumNumberOfEvents is the maximum number of events that ServiceStatus.Events can have
 	MaximumNumberOfEvents = 50
@@ -58,6 +58,41 @@ func NewServiceStatus(service *Service) *ServiceStatus {
 	}
 }
 
+// ShallowCopy creates a shallow copy of ServiceStatus
+func (ss *ServiceStatus) ShallowCopy() *ServiceStatus {
+	return &ServiceStatus{
+		Name:    ss.Name,
+		Group:   ss.Group,
+		Key:     ss.Key,
+		Results: ss.Results,
+		Events:  ss.Events,
+		Uptime:  ss.Uptime,
+	}
+}
+
+// WithResultPagination makes a shallow copy of the ServiceStatus with only the results
+// within the range defined by the page and pageSize parameters
+func (ss *ServiceStatus) WithResultPagination(page, pageSize int) *ServiceStatus {
+	shallowCopy := ss.ShallowCopy()
+	numberOfResults := len(shallowCopy.Results)
+	start := numberOfResults - (page * pageSize)
+	end := numberOfResults - ((page - 1) * pageSize)
+	if start > numberOfResults {
+		start = -1
+	} else if start < 0 {
+		start = 0
+	}
+	if end > numberOfResults {
+		end = numberOfResults
+	}
+	if start < 0 || end < 0 {
+		shallowCopy.Results = []*Result{}
+	} else {
+		shallowCopy.Results = shallowCopy.Results[start:end]
+	}
+	return shallowCopy
+}
+
 // AddResult adds a Result to ServiceStatus.Results and makes sure that there are
 // no more than 20 results in the Results slice
 func (ss *ServiceStatus) AddResult(result *Result) {

core/service-status_test.go

@@ -22,10 +22,45 @@ func TestNewServiceStatus(t *testing.T) {
 func TestServiceStatus_AddResult(t *testing.T) {
 	service := &Service{Name: "name", Group: "group"}
 	serviceStatus := NewServiceStatus(service)
-	for i := 0; i < 50; i++ {
+	for i := 0; i < MaximumNumberOfResults+10; i++ {
 		serviceStatus.AddResult(&Result{Timestamp: time.Now()})
 	}
-	if len(serviceStatus.Results) != 20 {
+	if len(serviceStatus.Results) != MaximumNumberOfResults {
 		t.Errorf("expected serviceStatus.Results to not exceed a length of 20")
 	}
 }
+
+func TestServiceStatus_WithResultPagination(t *testing.T) {
+	service := &Service{Name: "name", Group: "group"}
+	serviceStatus := NewServiceStatus(service)
+	for i := 0; i < 25; i++ {
+		serviceStatus.AddResult(&Result{Timestamp: time.Now()})
+	}
+	if len(serviceStatus.WithResultPagination(1, 1).Results) != 1 {
+		t.Errorf("expected to have 1 result")
+	}
+	if len(serviceStatus.WithResultPagination(5, 0).Results) != 0 {
+		t.Errorf("expected to have 0 results")
+	}
+	if len(serviceStatus.WithResultPagination(-1, 20).Results) != 0 {
+		t.Errorf("expected to have 0 result, because the page was invalid")
+	}
+	if len(serviceStatus.WithResultPagination(1, -1).Results) != 0 {
+		t.Errorf("expected to have 0 result, because the page size was invalid")
+	}
+	if len(serviceStatus.WithResultPagination(1, 10).Results) != 10 {
+		t.Errorf("expected to have 10 results, because given a page size of 10, page 1 should have 10 elements")
+	}
+	if len(serviceStatus.WithResultPagination(2, 10).Results) != 10 {
+		t.Errorf("expected to have 10 results, because given a page size of 10, page 2 should have 10 elements")
+	}
+	if len(serviceStatus.WithResultPagination(3, 10).Results) != 5 {
+		t.Errorf("expected to have 5 results, because given a page size of 10, page 3 should have 5 elements")
+	}
+	if len(serviceStatus.WithResultPagination(4, 10).Results) != 0 {
+		t.Errorf("expected to have 0 results, because given a page size of 10, page 4 should have 0 elements")
+	}
+	if len(serviceStatus.WithResultPagination(1, 50).Results) != 25 {
+		t.Errorf("expected to have 25 results, because there's only 25 results")
+	}
+}