diff --git a/verify_test.go b/verify_test.go
new file mode 100644
index 00000000..6557c64f
--- /dev/null
+++ b/verify_test.go
@@ -0,0 +1,218 @@
+// Copyright 2024 The Witness Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package witness
+
+import (
+	"bytes"
+	"context"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/json"
+	"fmt"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/in-toto/go-witness/attestation"
+	"github.com/in-toto/go-witness/attestation/commandrun"
+	"github.com/in-toto/go-witness/attestation/material"
+	"github.com/in-toto/go-witness/attestation/product"
+	"github.com/in-toto/go-witness/cryptoutil"
+	"github.com/in-toto/go-witness/dsse"
+	"github.com/in-toto/go-witness/policy"
+	"github.com/in-toto/go-witness/source"
+	"github.com/stretchr/testify/require"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestVerify(t *testing.T) {
+	policy, functionarySigner := makepolicyRSA(t)
+	policyEnvelope, policySigner := signPolicyRSA(t, policy)
+	policyVerifier, err := policySigner.Verifier()
+	require.NoError(t, err)
+	workingDir := t.TempDir()
+
+	step1Result, err := Run(
+		"step01",
+		RunWithSigners(functionarySigner),
+		RunWithAttestors([]attestation.Attestor{
+			material.New(),
+			commandrun.New(
+				commandrun.WithCommand([]string{"bash", "-c", "echo 'test01' > test.txt"}),
+			),
+			product.New(),
+		}),
+		RunWithAttestationOpts(
+			attestation.WithWorkingDir(workingDir),
+		),
+	)
+	require.NoError(t, err)
+
+	subjects := []cryptoutil.DigestSet{}
+	artifactSubject, err := cryptoutil.CalculateDigestSetFromFile(
+		filepath.Join(workingDir, "test.txt"),
+		[]cryptoutil.DigestValue{
+			{
+				GitOID: false,
+				Hash:   crypto.SHA256,
+			},
+		},
+	)
+	require.NoError(t, err)
+	subjects = append(subjects, artifactSubject)
+
+	step2Result, err := Run(
+		"step02",
+		RunWithSigners(functionarySigner),
+		RunWithAttestors([]attestation.Attestor{
+			material.New(),
+			commandrun.New(
+				commandrun.WithCommand([]string{"bash", "-c", "echo 'test02' >> test.txt"}),
+			),
+			product.New(),
+		}),
+		RunWithAttestationOpts(
+			attestation.WithWorkingDir(workingDir),
+		),
+	)
+	require.NoError(t, err)
+
+	artifactSubject, err = cryptoutil.CalculateDigestSetFromFile(
+		filepath.Join(workingDir, "test.txt"),
+		[]cryptoutil.DigestValue{
+			{
+				GitOID: false,
+				Hash:   crypto.SHA256,
+			},
+		},
+	)
+	require.NoError(t, err)
+	subjects = append(subjects, artifactSubject)
+
+	t.Run("Pass", func(t *testing.T) {
+		memorySource := source.NewMemorySource()
+		require.NoError(t, memorySource.LoadEnvelope("step01", step1Result.SignedEnvelope))
+		require.NoError(t, memorySource.LoadEnvelope("step02", step2Result.SignedEnvelope))
+
+		results, err := Verify(
+			context.Background(),
+			policyEnvelope,
+			[]cryptoutil.Verifier{policyVerifier},
+			VerifyWithCollectionSource(memorySource),
+			VerifyWithSubjectDigests(subjects),
+		)
+
+		require.NoError(t, err, fmt.Sprintf("failed with results: %+v", results))
+	})
+
+	t.Run("Fail with missing collection", func(t *testing.T) {
+		memorySource := source.NewMemorySource()
+		require.NoError(t, memorySource.LoadEnvelope("step01", step1Result.SignedEnvelope))
+
+		results, err := Verify(
+			context.Background(),
+			policyEnvelope,
+			[]cryptoutil.Verifier{policyVerifier},
+			VerifyWithCollectionSource(memorySource),
+			VerifyWithSubjectDigests(subjects),
+		)
+
+		require.Error(t, err, fmt.Sprintf("passed with results: %+v", results))
+	})
+}
+
+func makepolicy(functionary policy.Functionary, publicKey policy.PublicKey, roots map[string]policy.Root) policy.Policy {
+	step01 := policy.Step{
+		Name:          "step01",
+		Functionaries: []policy.Functionary{functionary},
+		Attestations:  []policy.Attestation{{Type: commandrun.Type}},
+	}
+
+	step02 := policy.Step{
+		Name:          "step02",
+		Functionaries: []policy.Functionary{functionary},
+		Attestations:  []policy.Attestation{{Type: commandrun.Type}},
+		ArtifactsFrom: []string{"step01"},
+	}
+
+	p := policy.Policy{
+		Expires:    metav1.Time{Time: time.Now().Add(1 * time.Hour)},
+		PublicKeys: map[string]policy.PublicKey{},
+		Steps:      map[string]policy.Step{},
+	}
+
+	if functionary.CertConstraint.Roots != nil {
+		p.Roots = roots
+	}
+
+	p.Steps = make(map[string]policy.Step)
+	p.Steps[step01.Name] = step01
+	p.Steps[step02.Name] = step02
+
+	if publicKey.KeyID != "" {
+		p.PublicKeys[publicKey.KeyID] = publicKey
+	}
+
+	return p
+}
+
+func makepolicyRSA(t *testing.T) (policy.Policy, cryptoutil.Signer) {
+	signer, err := createTestRSAKey()
+	require.NoError(t, err)
+	verifier, err := signer.Verifier()
+	require.NoError(t, err)
+	keyID, err := verifier.KeyID()
+	require.NoError(t, err)
+	functionary := policy.Functionary{
+		Type:        "PublicKey",
+		PublicKeyID: keyID,
+	}
+
+	pub, err := verifier.Bytes()
+	require.NoError(t, err)
+
+	pk := policy.PublicKey{
+		KeyID: keyID,
+		Key:   pub,
+	}
+
+	p := makepolicy(functionary, pk, nil)
+	return p, signer
+}
+
+func signPolicyRSA(t *testing.T, p policy.Policy) (dsse.Envelope, cryptoutil.Signer) {
+	signer, err := createTestRSAKey()
+	require.NoError(t, err)
+	pBytes, err := json.Marshal(p)
+	require.NoError(t, err)
+	reader := bytes.NewReader(pBytes)
+	outBytes := []byte{}
+	writer := bytes.NewBuffer(outBytes)
+	require.NoError(t, Sign(reader, policy.PolicyPredicate, writer, dsse.SignWithSigners(signer)))
+	env := dsse.Envelope{}
+	require.NoError(t, json.Unmarshal(writer.Bytes(), &env))
+	return env, signer
+}
+
+func createTestRSAKey() (cryptoutil.Signer, error) {
+	privKey, err := rsa.GenerateKey(rand.Reader, 512)
+	if err != nil {
+		return nil, err
+	}
+
+	signer := cryptoutil.NewRSASigner(privKey, crypto.SHA256)
+	return signer, nil
+}