diff --git a/source/calendarwebapp/jsonexport.d b/source/calendarwebapp/jsonexport.d
index 21540ee..274fffd 100644
--- a/source/calendarwebapp/jsonexport.d
+++ b/source/calendarwebapp/jsonexport.d
@@ -3,10 +3,14 @@ module calendarwebapp.jsonexport;
 import calendarwebapp.event : Event, EventStore;
 
 import core.time;
+
+import std.algorithm.iteration : each;
+
 import std.datetime.date;
 import std.datetime.interval;
 import std.datetime.systime;
 
+import std.format : format;
 import poodinis : Autowire;
 
 import vibe.data.serialization : name;
@@ -19,19 +23,23 @@ private:
 
 public:
     this(in Date begin, in Date end)
+    in
+    {
+        assert(begin < end,
+                "DayJSONManager: begin (%s) needs to be earlier than end (%s)".format(begin, end));
+    }
+    do
     {
         this.begin = begin;
         this.end = end;
+        Interval!Date(this.begin, this.end).fwdRange(date => date + 1.dur!"days")
+            .each!(date => events[date] = []);
     }
 
     void addEvent(Event event)
     {
         if (Interval!Date(begin, end).contains(event.begin))
         {
-            if (event.end.isNull)
-            {
-                event.end = event.begin;
-            }
             events[event.begin] ~= event;
         }
     }
@@ -75,6 +83,25 @@ public:
     }
 }
 
+struct DayData
+{
+    short year;
+    Month month;
+    string monthName;
+    ubyte day;
+    @name("daytype") DayType dayType;
+    Event[] eventList;
+    @name("wday") string weekDayName;
+    Line[] lines;
+}
+
+enum DayType
+{
+    Workday,
+    Holiday,
+    Weekend
+}
+
 private:
 
 string toGerString(Month m)
@@ -129,13 +156,6 @@ string toGerString(DayOfWeek d)
     }
 }
 
-enum DayType
-{
-    Workday,
-    Holiday,
-    Weekend
-}
-
 DayType dayType(DayOfWeek dayOfWeek)
 {
     switch (dayOfWeek) with (DayOfWeek)
@@ -149,18 +169,6 @@ DayType dayType(DayOfWeek dayOfWeek)
     }
 }
 
-struct DayData
-{
-    short year;
-    Month month;
-    string monthName;
-    ubyte day;
-    @name("daytype") DayType dayType;
-    Event[] eventList;
-    @name("wday") string weekDayName;
-    Line[] lines;
-}
-
 struct Line
 {
 }
diff --git a/test/calendarwebapp/testjsonexport.d b/test/calendarwebapp/testjsonexport.d
index 35aa00f..1bfe2f7 100644
--- a/test/calendarwebapp/testjsonexport.d
+++ b/test/calendarwebapp/testjsonexport.d
@@ -5,17 +5,133 @@ import calendarwebapp.jsonexport;
 
 import poodinis;
 
-import std.algorithm;
-import std.datetime.date : Date;
+import core.exception : AssertError;
+
+import std.algorithm.iteration : each;
+import std.datetime.date : Date, Month;
 import std.exception : enforce;
 import std.range.interfaces : InputRange, inputRangeObject;
+import std.range.primitives : empty;
 
 import unit_threaded;
 
-@("calendarwebapp.JSONExporter")
+@("JSONExporter.empty")
 @system unittest
 {
     auto container = new shared DependencyContainer();
     container.register!(EventStore, StubEventStore);
-    container.register!(JSONExporter);
+    container.register!JSONExporter;
+    auto exporter = container.resolve!JSONExporter;
+    exporter.write.each!(dayData => dayData.eventList.empty.shouldBeTrue);
+}
+
+@("JSONExporter.1 event")
+@system unittest
+{
+    auto container = new shared DependencyContainer();
+    container.register!(EventStore, StubEventStore);
+    container.register!JSONExporter;
+    auto exporter = container.resolve!JSONExporter;
+    auto eventStore = container.resolve!EventStore;
+    immutable event = Event("599090de97355141140fc698", Date(2018, 1, 14));
+    eventStore.addEvent(event);
+    exporter.write.each!(dayData => (dayData.year == 2018
+            && dayData.month == Month.jan && dayData.day == 14) ? dayData.eventList.shouldEqual([event])
+            : dayData.eventList.empty.shouldBeTrue);
+}
+
+@("DayJSONManager with begin > end")
+@system unittest
+{
+    DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 13)).shouldThrow!AssertError;
+}
+
+@("DayJSONManager with begin = end")
+@system unittest
+{
+    DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 14)).shouldThrow!AssertError;
+}
+
+@("DayJSONManager.getDayData with date < begin and 0 events")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    dayJSONManager.getDayData(Date(2018, 1, 13)).shouldThrow;
+}
+
+@("DayJSONManager.getDayData with date > end and 0 events")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    dayJSONManager.getDayData(Date(2018, 1, 17)).shouldThrow;
+}
+
+@("DayJSONManager.getDayData with date = end and 0 events")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    dayJSONManager.getDayData(Date(2018, 1, 16)).shouldThrow;
+}
+
+@("DayJSONManager.getDayData with date = begin and 0 events")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    dayJSONManager.getDayData(Date(2018, 1, 14)).shouldEqual(DayData(2018,
+            Month.jan, "Januar", 14, DayType.Holiday, [], "Sonntag", []));
+}
+
+@("DayJSONManager.getDayData with begin < date < end and 0 events")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    dayJSONManager.getDayData(Date(2018, 1, 15)).shouldEqual(DayData(2018,
+            Month.jan, "Januar", 15, DayType.Workday, [], "Montag", []));
+}
+
+@("DayJSONManager.getDayData with date < begin and 1 event")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    immutable event = Event("599090de97355141140fc698", Date(2018, 1, 14));
+    dayJSONManager.addEvent(event);
+    dayJSONManager.getDayData(Date(2018, 1, 13)).shouldThrow;
+}
+
+@("DayJSONManager.getDayData with date > end and 1 event")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    immutable event = Event("599090de97355141140fc698", Date(2018, 1, 14));
+    dayJSONManager.addEvent(event);
+    dayJSONManager.getDayData(Date(2018, 1, 17)).shouldThrow;
+}
+
+@("DayJSONManager.getDayData with date = end and 1 event")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    immutable event = Event("599090de97355141140fc698", Date(2018, 1, 14));
+    dayJSONManager.addEvent(event);
+    dayJSONManager.getDayData(Date(2018, 1, 16)).shouldThrow;
+}
+
+@("DayJSONManager.getDayData with date = begin and 1 event")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 15));
+    immutable event = Event("599090de97355141140fc698", Date(2018, 1, 14));
+    dayJSONManager.addEvent(event);
+    dayJSONManager.getDayData(Date(2018, 1, 14)).shouldEqual(DayData(2018,
+            Month.jan, "Januar", 14, DayType.Holiday, [event], "Sonntag", []));
+}
+
+@("DayJSONManager.getDayData with begin < date < end and 1 event")
+@system unittest
+{
+    auto dayJSONManager = DayJSONManager(Date(2018, 1, 14), Date(2018, 1, 16));
+    immutable event = Event("599090de97355141140fc698", Date(2018, 1, 15));
+    dayJSONManager.addEvent(event);
+    dayJSONManager.getDayData(Date(2018, 1, 15)).shouldEqual(DayData(2018,
+            Month.jan, "Januar", 15, DayType.Workday, [event], "Montag", []));
 }