trimmed pem files and added validation tests

internal/client/client.go

@@ -1,6 +1,7 @@
 package client
 
 import (
+	"bytes"
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
@@ -135,6 +136,11 @@ func GetLocalCerts(certFile string) ([]*x509.Certificate, error) {
 	var certs []*x509.Certificate
 	// Open and read PEM file
 	data, err := os.ReadFile(certFile)
+
+	// Remove any prefix or trailing new lines
+	data = bytes.TrimLeft(data, "\n")
+	data = bytes.TrimRight(data, "\n")
+
 	if err != nil {
 		return nil, err
 	}

internal/client/client_test.go

@@ -0,0 +1,30 @@
+package client
+
+import (
+	"testing"
+)
+
+// Test the GetLocalCerts function to ensure that the resulting certs contains a proper slice of *x509.Certificate
+func TestGetLocalCerts(t *testing.T) {
+	tt := []struct {
+		certFile string
+		expected string // serialNumber
+	}{
+		{"../../test_data/rsa_2048_exp3.crt", "689353446962534075818318094020409231943178713332"},
+		{"../../test_data/rsa_4096_exp9.crt", "491857893787078309585312564136279056496696784059"},
+		{"../../test_data/ecdsa.crt", "161666955289179666643937194263860491865277586603"},
+		{"../../test_data/ed25519.crt", "170414627618143861399763465404232742787060139745"},
+	}
+	for _, tc := range tt {
+		t.Run(tc.certFile, func(t *testing.T) {
+			certs, err := GetLocalCerts(tc.certFile)
+			if err != nil {
+				t.Errorf("error creating cert from local pem file %s: %s", tc.certFile, err)
+			}
+			got := certs[0].SerialNumber.String()
+			if got != tc.expected {
+				t.Errorf("got %s, expected %s", got, tc.expected)
+			}
+		})
+	}
+}