databroker: add support for querying the databroker (#1443)

* databroker: add support for querying the databroker

* remove query method, use getall so encryption works

* add test

* return early

pkg/grpc/databroker/databroker_test.go

@@ -0,0 +1,46 @@
+package databroker
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestApplyOffsetAndLimit(t *testing.T) {
+	cases := []struct {
+		name          string
+		records       []*Record
+		offset, limit int
+		expect        []*Record
+	}{
+		{
+			name:    "empty",
+			records: nil,
+			offset:  10,
+			limit:   5,
+			expect:  nil,
+		},
+		{
+			name:    "less than limit",
+			records: []*Record{{Id: "A"}, {Id: "B"}, {Id: "C"}, {Id: "D"}},
+			offset:  1,
+			limit:   10,
+			expect:  []*Record{{Id: "B"}, {Id: "C"}, {Id: "D"}},
+		},
+		{
+			name:    "more than limit",
+			records: []*Record{{Id: "A"}, {Id: "B"}, {Id: "C"}, {Id: "D"}, {Id: "E"}, {Id: "F"}, {Id: "G"}, {Id: "H"}},
+			offset:  3,
+			limit:   2,
+			expect:  []*Record{{Id: "D"}, {Id: "E"}},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			actual, cnt := ApplyOffsetAndLimit(tc.records, tc.offset, tc.limit)
+			assert.Equal(t, len(tc.records), cnt)
+			assert.Equal(t, tc.expect, actual)
+		})
+	}
+}