diff --git a/.gitignore b/.gitignore
index 37463fa6..a8e05fde 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,3 +12,4 @@ test/scorecard.json
 log
 sarif-report.json
 test/log
+.idea/
diff --git a/source/memory_test.go b/source/memory_test.go
new file mode 100644
index 00000000..737e0386
--- /dev/null
+++ b/source/memory_test.go
@@ -0,0 +1,161 @@
+// Copyright 2021 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 source
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/testifysec/go-witness/attestation"
+	"github.com/testifysec/go-witness/dsse"
+	intoto "github.com/testifysec/go-witness/intoto"
+)
+
+func TestLoadFile(t *testing.T) {
+	predicate, err := json.Marshal(attestation.Collection{})
+	if err != nil {
+		fmt.Errorf("failed to marshal predicate, err = %v", err)
+	}
+	tests := []struct {
+		name                 string
+		reference            string
+		intotoStatment       intoto.Statement
+		mSource              *MemorySource
+		attCol               attestation.Collection
+		wantLoadEnvelopeErr  bool
+		wantPredicateErr     bool
+		wantMemorySourceErr  bool
+		wantRefrenceExistErr bool
+	}{
+		{
+			name:      "Valid intotoStatment",
+			reference: "ref",
+			intotoStatment: intoto.Statement{
+				Type:          "https://in-toto.io/Statement/v0.1",
+				Subject:       []intoto.Subject{{Name: "example", Digest: map[string]string{"sha256": "exampledigest"}}},
+				PredicateType: "https://slsa.dev/provenance/v0.2",
+				Predicate:     json.RawMessage(predicate),
+			},
+			attCol:  attestation.Collection{},
+			mSource: NewMemorySource(),
+		},
+		{
+			name:                "Empty Invalid intotoStatment",
+			reference:           "ref",
+			intotoStatment:      intoto.Statement{},
+			mSource:             NewMemorySource(),
+			attCol:              attestation.Collection{},
+			wantPredicateErr:    true,
+			wantMemorySourceErr: true,
+		},
+		{
+			name:      "Invalid intotoStatment Predicate",
+			reference: "ref",
+			intotoStatment: intoto.Statement{
+				Type:          "https://in-toto.io/Statement/v0.1",
+				Subject:       []intoto.Subject{{Name: "example", Digest: map[string]string{"sha256": "exampledigest"}}},
+				PredicateType: "https://slsa.dev/provenance/v0.2",
+				Predicate:     json.RawMessage("invalid-predicate"),
+			},
+			attCol:              attestation.Collection{},
+			mSource:             NewMemorySource(),
+			wantLoadEnvelopeErr: true,
+			wantMemorySourceErr: true,
+		},
+		{
+			name:      "Valid intotoStatment",
+			reference: "ref",
+			intotoStatment: intoto.Statement{
+				Type:          "https://in-toto.io/Statement/v0.1",
+				Subject:       []intoto.Subject{{Name: "example", Digest: map[string]string{"sha256": "exampledigest"}}},
+				PredicateType: "https://slsa.dev/provenance/v0.2",
+				Predicate:     json.RawMessage(predicate),
+			},
+			mSource:              NewMemorySource(),
+			wantLoadEnvelopeErr:  true,
+			wantRefrenceExistErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+
+			// Marshal the intoto.Statement into a JSON byte array
+			var err error
+
+			statementBytes, _ := json.Marshal(tt.intotoStatment)
+
+			// Create a new dsse.Envelope with the marshalled intoto.Statement as the payload
+			envelope := dsse.Envelope{
+				Payload:     statementBytes,
+				PayloadType: "application/vnd.in-toto+json",
+			}
+
+			// Initialize a new MemorySource
+			memorySource := NewMemorySource()
+			if tt.wantRefrenceExistErr {
+				collEnv, err := envelopeToCollectionEnvelope(tt.reference, envelope)
+				if err != nil {
+					t.Errorf("Invalid intotoStatment, err = %v", err)
+				}
+				// since this envelope is not in the MemorySource, we can add the collection envelope into the map
+				memorySource.envelopesByReference[tt.reference] = collEnv
+			}
+
+			// Load the dsse.Envelope into the MemorySource
+			err = memorySource.LoadEnvelope(tt.reference, envelope)
+			if err != nil {
+				// if we did not want the error
+				if !tt.wantLoadEnvelopeErr {
+					t.Errorf("LoadEnvelope() error = %v, wantErr %v", err, tt.wantLoadEnvelopeErr)
+					return
+				}
+				return
+
+			}
+
+			// Check if the loaded envelope matches the expected CollectionEnvelope
+
+			expectedCollectionEnvelope := CollectionEnvelope{
+				Envelope:   envelope,
+				Statement:  tt.intotoStatment,
+				Collection: tt.attCol,
+				Reference:  tt.reference,
+			}
+			if !reflect.DeepEqual(memorySource.envelopesByReference[tt.reference], expectedCollectionEnvelope) != tt.wantMemorySourceErr {
+				t.Errorf("Mismatch or non-existence of collection envelope for reference in envelopesByReference map.")
+				return
+			}
+			// Verify if the subjects and attestations are present in the loaded envelope
+			for _, sub := range tt.intotoStatment.Subject {
+				for _, digest := range sub.Digest {
+					if _, ok := memorySource.subjectDigestsByReference[tt.reference][digest]; !ok != tt.wantMemorySourceErr {
+						t.Errorf("memorySource does not contain passed in digest = %v", digest)
+						return
+					}
+				}
+			}
+			for _, att := range tt.attCol.Attestations {
+				if _, ok := memorySource.attestationsByReference[tt.reference][att.Attestation.Type()]; !ok != tt.wantMemorySourceErr {
+					t.Errorf("memorySource does not contain passed in attestation = %v", att.Attestation.Name())
+					return
+				}
+			}
+
+		})
+	}
+}