diff --git a/info/container_test.go b/info/container_test.go
index 3eff2658..c1d1029c 100644
--- a/info/container_test.go
+++ b/info/container_test.go
@@ -84,3 +84,167 @@ func TestPercentiles(t *testing.T) {
 		}
 	}
 }
+
+func TestAddSampleNilStats(t *testing.T) {
+	s := &ContainerStatsSummary{}
+
+	stats := &ContainerStats{
+		Cpu:    &CpuStats{},
+		Memory: &MemoryStats{},
+	}
+	stats.Cpu.Usage.PerCpu = []uint64{uint64(10)}
+	stats.Cpu.Usage.Total = uint64(10)
+	stats.Cpu.Usage.System = uint64(2)
+	stats.Cpu.Usage.User = uint64(8)
+	stats.Memory.Usage = uint64(200)
+	s.AddSample(nil, stats)
+
+	if len(s.Samples) != 0 {
+		t.Errorf("added an unexpected sample: %+v", s.Samples)
+	}
+
+	s.Samples = nil
+	s.AddSample(stats, nil)
+
+	if len(s.Samples) != 0 {
+		t.Errorf("added an unexpected sample: %+v", s.Samples)
+	}
+}
+
+func TestAddSample(t *testing.T) {
+	s := &ContainerStatsSummary{}
+
+	cpuPrevUsage := uint64(10)
+	cpuCurrentUsage := uint64(15)
+	memCurrentUsage := uint64(200)
+
+	prev := &ContainerStats{
+		Cpu:    &CpuStats{},
+		Memory: &MemoryStats{},
+	}
+	prev.Cpu.Usage.PerCpu = []uint64{cpuPrevUsage}
+	prev.Cpu.Usage.Total = cpuPrevUsage
+	prev.Cpu.Usage.System = 0
+	prev.Cpu.Usage.User = cpuPrevUsage
+	prev.Timestamp = time.Now()
+
+	current := &ContainerStats{
+		Cpu:    &CpuStats{},
+		Memory: &MemoryStats{},
+	}
+	current.Cpu.Usage.PerCpu = []uint64{cpuCurrentUsage}
+	current.Cpu.Usage.Total = cpuCurrentUsage
+	current.Cpu.Usage.System = 0
+	current.Cpu.Usage.User = cpuCurrentUsage
+	current.Memory.Usage = memCurrentUsage
+	current.Timestamp = prev.Timestamp.Add(1 * time.Second)
+
+	s.AddSample(prev, current)
+
+	if len(s.Samples) != 1 {
+		t.Fatalf("unexpected samples: %+v", s.Samples)
+	}
+
+	if s.Samples[0].Memory.Usage != memCurrentUsage {
+		t.Errorf("wrong memory usage: %v. should be %v", s.Samples[0].Memory.Usage, memCurrentUsage)
+	}
+
+	if s.Samples[0].Cpu.Usage != cpuCurrentUsage-cpuPrevUsage {
+		t.Errorf("wrong CPU usage: %v. should be %v", s.Samples[0].Cpu.Usage, cpuCurrentUsage-cpuPrevUsage)
+	}
+}
+
+func TestAddSampleIncompleteStats(t *testing.T) {
+	s := &ContainerStatsSummary{}
+
+	cpuPrevUsage := uint64(10)
+	cpuCurrentUsage := uint64(15)
+	memCurrentUsage := uint64(200)
+
+	prev := &ContainerStats{
+		Cpu:    &CpuStats{},
+		Memory: &MemoryStats{},
+	}
+	prev.Cpu.Usage.PerCpu = []uint64{cpuPrevUsage}
+	prev.Cpu.Usage.Total = cpuPrevUsage
+	prev.Cpu.Usage.System = 0
+	prev.Cpu.Usage.User = cpuPrevUsage
+	prev.Timestamp = time.Now()
+
+	current := &ContainerStats{
+		Cpu:    &CpuStats{},
+		Memory: &MemoryStats{},
+	}
+	current.Cpu.Usage.PerCpu = []uint64{cpuCurrentUsage}
+	current.Cpu.Usage.Total = cpuCurrentUsage
+	current.Cpu.Usage.System = 0
+	current.Cpu.Usage.User = cpuCurrentUsage
+	current.Memory.Usage = memCurrentUsage
+	current.Timestamp = prev.Timestamp.Add(1 * time.Second)
+
+	stats := &ContainerStats{
+		Cpu:    prev.Cpu,
+		Memory: nil,
+	}
+	s.AddSample(stats, current)
+	if len(s.Samples) != 0 {
+		t.Errorf("added an unexpected sample: %+v", s.Samples)
+	}
+	s.Samples = nil
+
+	s.AddSample(prev, stats)
+	if len(s.Samples) != 0 {
+		t.Errorf("added an unexpected sample: %+v", s.Samples)
+	}
+	s.Samples = nil
+
+	stats = &ContainerStats{
+		Cpu:    nil,
+		Memory: prev.Memory,
+	}
+	s.AddSample(stats, current)
+	if len(s.Samples) != 0 {
+		t.Errorf("added an unexpected sample: %+v", s.Samples)
+	}
+	s.Samples = nil
+
+	s.AddSample(prev, stats)
+	if len(s.Samples) != 0 {
+		t.Errorf("added an unexpected sample: %+v", s.Samples)
+	}
+	s.Samples = nil
+}
+
+func TestAddSampleWrongOrder(t *testing.T) {
+	s := &ContainerStatsSummary{}
+
+	cpuPrevUsage := uint64(10)
+	cpuCurrentUsage := uint64(15)
+	memCurrentUsage := uint64(200)
+
+	prev := &ContainerStats{
+		Cpu:    &CpuStats{},
+		Memory: &MemoryStats{},
+	}
+	prev.Cpu.Usage.PerCpu = []uint64{cpuPrevUsage}
+	prev.Cpu.Usage.Total = cpuPrevUsage
+	prev.Cpu.Usage.System = 0
+	prev.Cpu.Usage.User = cpuPrevUsage
+	prev.Timestamp = time.Now()
+
+	current := &ContainerStats{
+		Cpu:    &CpuStats{},
+		Memory: &MemoryStats{},
+	}
+	current.Cpu.Usage.PerCpu = []uint64{cpuCurrentUsage}
+	current.Cpu.Usage.Total = cpuCurrentUsage
+	current.Cpu.Usage.System = 0
+	current.Cpu.Usage.User = cpuCurrentUsage
+	current.Memory.Usage = memCurrentUsage
+	current.Timestamp = prev.Timestamp.Add(1 * time.Second)
+
+	s.AddSample(current, prev)
+	if len(s.Samples) != 0 {
+		t.Errorf("added an unexpected sample: %+v", s.Samples)
+	}
+}