diff --git a/app/envoy-scraper/digest_http_test.go b/app/envoy-scraper/digest_http_test.go
new file mode 100644
index 0000000..5b038a9
--- /dev/null
+++ b/app/envoy-scraper/digest_http_test.go
@@ -0,0 +1,101 @@
+package main
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_getCnonce(t *testing.T) {
+	t.Run("getCnonce", func(t *testing.T) {
+		got := getCnonce()
+		require.Len(t, got, 16)
+	})
+}
+
+func Test_getMD5(t *testing.T) {
+	tests := []struct {
+		arg  string
+		want string
+	}{
+		{"foo", "acbd18db4cc2f85cedef654fccc4a4d8"},
+		{"bar", "37b51d194a7513e45b56f6524f2d51f2"},
+		{strings.Repeat("uhoh", 10), "18212ada675a1b66a3ea6e61d1560b4e"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.arg, func(t *testing.T) {
+			got := getMD5(tt.arg)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}
+
+func Test_getDigestParts(t *testing.T) {
+	tests := []struct {
+		name    string
+		headers http.Header
+		want    map[string]string
+	}{
+		{
+			"no authenticate header",
+			http.Header{},
+			map[string]string{},
+		}, {
+			"header with nonce",
+			http.Header{"Www-Authenticate": []string{`Digest, nonce="foo"`}},
+			map[string]string{"nonce": "foo"},
+		}, {
+			"header with extra parts",
+			http.Header{"Www-Authenticate": []string{`Digest, nonce="foo", whatever="this"`}},
+			map[string]string{"nonce": "foo"},
+		}, {
+			"all wanted components",
+			http.Header{"Www-Authenticate": []string{`Digest, nonce="foo",realm="example.com",qop="auth"`}},
+			map[string]string{"nonce": "foo", "realm": "example.com", "qop": "auth"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := getDigestParts(tt.headers)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}
+
+func Test_getDigestAuthorization(t *testing.T) {
+	type args struct {
+		nonce string
+		parts map[string]string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			"all parts",
+			args{
+				"abcdef",
+				map[string]string{
+					"username": "alice",
+					"realm":    "example.com",
+					"password": "secret",
+					"method":   "GET",
+					"uri":      "/foo",
+					"nonce":    "abcdef",
+					"qop":      "auth",
+				},
+			},
+			`Digest username="alice", realm="example.com", nonce="abcdef", uri="/foo", cnonce="abcdef", nc="1", qop="auth", response="d1a132d3ab82343c98d18abe957b67d0"`,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := getDigestAuthorization(tt.args.nonce, tt.args.parts)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}
diff --git a/go.mod b/go.mod
index 9133aac..139cec4 100644
--- a/go.mod
+++ b/go.mod
@@ -5,16 +5,20 @@ go 1.20
 require (
 	github.com/gorilla/handlers v1.5.1
 	github.com/gorilla/mux v1.8.0
-	github.com/influxdata/influxdb-client-go/v2 v2.12.2
+	github.com/influxdata/influxdb-client-go/v2 v2.12.3
 	github.com/skandragon/gohealthcheck v1.0.3
+	github.com/stretchr/testify v1.8.1
 )
 
 require (
 	github.com/apapsch/go-jsonmerge/v2 v2.0.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/deepmap/oapi-codegen v1.12.4 // indirect
 	github.com/felixge/httpsnoop v1.0.3 // indirect
 	github.com/google/uuid v1.3.0 // indirect
 	github.com/influxdata/line-protocol v0.0.0-20210922203350-b1ad95c89adf // indirect
 	github.com/pkg/errors v0.9.1 // indirect
-	golang.org/x/net v0.8.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	golang.org/x/net v0.9.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
diff --git a/go.sum b/go.sum
index f1d9fc1..225c2ea 100644
--- a/go.sum
+++ b/go.sum
@@ -4,6 +4,7 @@ github.com/apapsch/go-jsonmerge/v2 v2.0.0/go.mod h1:lvDnEdqiQrp0O42VQGgmlKpxL1AP
 github.com/bmatcuk/doublestar v1.1.1/go.mod h1:UD6OnuiIn0yFxxA2le/rnRU1G4RaI4UvFv1sNto9p6w=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/deepmap/oapi-codegen v1.12.4 h1:pPmn6qI9MuOtCz82WY2Xaw46EQjgvxednXXrP7g5Q2s=
 github.com/deepmap/oapi-codegen v1.12.4/go.mod h1:3lgHGMu6myQ2vqbbTXH2H1o4eXFTGnFiDaOaKKl5yas=
 github.com/felixge/httpsnoop v1.0.1/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
@@ -15,8 +16,8 @@ github.com/gorilla/handlers v1.5.1 h1:9lRY6j8DEeeBT10CvO9hGW0gmky0BprnvDI5vfhUHH
 github.com/gorilla/handlers v1.5.1/go.mod h1:t8XrUpc4KVXb7HGyJ4/cEnwQiaxrX/hz1Zv/4g96P1Q=
 github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
 github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
-github.com/influxdata/influxdb-client-go/v2 v2.12.2 h1:uYABKdrEKlYm+++qfKdbgaHKBPmoWR5wpbmj6MBB/2g=
-github.com/influxdata/influxdb-client-go/v2 v2.12.2/go.mod h1:YteV91FiQxRdccyJ2cHvj2f/5sq4y4Njqu1fQzsQCOU=
+github.com/influxdata/influxdb-client-go/v2 v2.12.3 h1:28nRlNMRIV4QbtIUvxhWqaxn0IpXeMSkY/uJa/O/vC4=
+github.com/influxdata/influxdb-client-go/v2 v2.12.3/go.mod h1:IrrLUbCjjfkmRuaCiGQg4m2GbkaeJDcuWoxiWdQEbA0=
 github.com/influxdata/line-protocol v0.0.0-20210922203350-b1ad95c89adf h1:7JTmneyiNEwVBOHSjoMxiWAqB992atOeepeFYegn5RU=
 github.com/influxdata/line-protocol v0.0.0-20210922203350-b1ad95c89adf/go.mod h1:xaLFMmpvUxqXtVkUJfg9QmT88cDaCJ3ZKgdZ78oO8Qo=
 github.com/juju/gnuflag v0.0.0-20171113085948-2ce1bb71843d/go.mod h1:2PavIy+JPciBPrBUjwbNvtwB6RQlve+hkpll6QSNmOE=
@@ -28,8 +29,17 @@ github.com/skandragon/gohealthcheck v1.0.3 h1:Q4gIYvX2eBfEuM9msyK6NapTPWK0zgpyuU
 github.com/skandragon/gohealthcheck v1.0.3/go.mod h1:fEu59f3K+54jXlAOs0YDHojk7XximptsxYzCBXd9+oI=
 github.com/spkg/bom v0.0.0-20160624110644-59b7046e48ad/go.mod h1:qLr4V1qq6nMqFKkMo8ZTx3f+BZEkzsRUY10Xsm2mwU0=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
-golang.org/x/net v0.8.0 h1:Zrh2ngAOFYneWTAIAPethzeaQLuHwhuBkuV6ZiRnUaQ=
-golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+golang.org/x/net v0.9.0 h1:aWJ/m6xSmxWBx+V0XRHTlrYrPG56jKsLdTFmsSsCzOM=
+golang.org/x/net v0.9.0/go.mod h1:d48xBJpPfHeWQsugry2m+kC02ZBRGRgulfHnEXEuWns=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=