1 files changed, 134 insertions, 0 deletions
diff --git a/src/go/collectors/go.d.plugin/agent/confgroup/cache_test.go b/src/go/collectors/go.d.plugin/agent/confgroup/cache_test.go
new file mode 100644
index 000000000..a2bbd4919
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/agent/confgroup/cache_test.go
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package confgroup
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConfigCache_Add(t *testing.T) {
+	tests := map[string]struct {
+		prepareGroups  []Group
+		groups         []Group
+		expectedAdd    []Config
+		expectedRemove []Config
+	}{
+		"new group, new configs": {
+			groups: []Group{
+				prepareGroup("source", prepareCfg("name", "module")),
+			},
+			expectedAdd: []Config{
+				prepareCfg("name", "module"),
+			},
+		},
+		"several equal updates for the same group": {
+			groups: []Group{
+				prepareGroup("source", prepareCfg("name", "module")),
+				prepareGroup("source", prepareCfg("name", "module")),
+				prepareGroup("source", prepareCfg("name", "module")),
+				prepareGroup("source", prepareCfg("name", "module")),
+				prepareGroup("source", prepareCfg("name", "module")),
+			},
+			expectedAdd: []Config{
+				prepareCfg("name", "module"),
+			},
+		},
+		"empty group update for cached group": {
+			prepareGroups: []Group{
+				prepareGroup("source", prepareCfg("name1", "module"), prepareCfg("name2", "module")),
+			},
+			groups: []Group{
+				prepareGroup("source"),
+			},
+			expectedRemove: []Config{
+				prepareCfg("name1", "module"),
+				prepareCfg("name2", "module"),
+			},
+		},
+		"changed group update for cached group": {
+			prepareGroups: []Group{
+				prepareGroup("source", prepareCfg("name1", "module"), prepareCfg("name2", "module")),
+			},
+			groups: []Group{
+				prepareGroup("source", prepareCfg("name2", "module")),
+			},
+			expectedRemove: []Config{
+				prepareCfg("name1", "module"),
+			},
+		},
+		"empty group update for uncached group": {
+			groups: []Group{
+				prepareGroup("source"),
+				prepareGroup("source"),
+			},
+		},
+		"several updates with different source but same context": {
+			groups: []Group{
+				prepareGroup("source1", prepareCfg("name1", "module"), prepareCfg("name2", "module")),
+				prepareGroup("source2", prepareCfg("name1", "module"), prepareCfg("name2", "module")),
+			},
+			expectedAdd: []Config{
+				prepareCfg("name1", "module"),
+				prepareCfg("name2", "module"),
+			},
+		},
+		"have equal configs from 2 sources, get empty group for the 1st source": {
+			prepareGroups: []Group{
+				prepareGroup("source1", prepareCfg("name1", "module"), prepareCfg("name2", "module")),
+				prepareGroup("source2", prepareCfg("name1", "module"), prepareCfg("name2", "module")),
+			},
+			groups: []Group{
+				prepareGroup("source2"),
+			},
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			cache := NewCache()
+
+			for _, group := range test.prepareGroups {
+				cache.Add(&group)
+			}
+
+			var added, removed []Config
+			for _, group := range test.groups {
+				a, r := cache.Add(&group)
+				added = append(added, a...)
+				removed = append(removed, r...)
+			}
+
+			sortConfigs(added)
+			sortConfigs(removed)
+			sortConfigs(test.expectedAdd)
+			sortConfigs(test.expectedRemove)
+
+			assert.Equalf(t, test.expectedAdd, added, "added configs")
+			assert.Equalf(t, test.expectedRemove, removed, "removed configs")
+		})
+	}
+}
+
+func prepareGroup(source string, cfgs ...Config) Group {
+	return Group{
+		Configs: cfgs,
+		Source:  source,
+	}
+}
+
+func prepareCfg(name, module string) Config {
+	return Config{
+		"name":   name,
+		"module": module,
+	}
+}
+
+func sortConfigs(cfgs []Config) {
+	if len(cfgs) == 0 {
+		return
+	}
+	sort.Slice(cfgs, func(i, j int) bool { return cfgs[i].FullName() < cfgs[j].FullName() })
+}