From f182a6e7d083ecee32cbe19a1bd362f71027ac74 Mon Sep 17 00:00:00 2001
From: Trevor Pilley <TrevorPilley@users.noreply.github.com>
Date: Tue, 5 Nov 2024 17:48:47 +0000
Subject: [PATCH] Add SharesNdcWith

---
 src/PhoneNumbers/PhoneNumber.cs             |  8 +++++++
 test/PhoneNumbers.Tests/PhoneNumberTests.cs | 23 +++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/PhoneNumbers/PhoneNumber.cs b/src/PhoneNumbers/PhoneNumber.cs
index d50c8ccb..efe4c048 100644
--- a/src/PhoneNumbers/PhoneNumber.cs
+++ b/src/PhoneNumbers/PhoneNumber.cs
@@ -216,4 +216,12 @@ public override string ToString() =>
     /// <returns>The string representation of the value of this instance as specified by the format.</returns>
     public string ToString(string format) =>
         CountryInfo.GetFormatter(format).Format(this);
+
+    /// <summary>
+    /// Gets a value indicting whether this <see cref="PhoneNumber"/> shares a national destination code with the specified <see cref="PhoneNumber"/>.
+    /// </summary>
+    /// <param name="phoneNumber">The <see cref="PhoneNumber"/> to compare against.</param>
+    /// <returns>True if the both phone numbers share a national destination code, otherwise false.</returns>
+    internal bool SharesNdcWith(PhoneNumber phoneNumber) =>
+        NationalDestinationCode?.Equals(phoneNumber.NationalDestinationCode, StringComparison.Ordinal) == true;
 }
diff --git a/test/PhoneNumbers.Tests/PhoneNumberTests.cs b/test/PhoneNumbers.Tests/PhoneNumberTests.cs
index 2cd628c1..b1c1efd6 100644
--- a/test/PhoneNumbers.Tests/PhoneNumberTests.cs
+++ b/test/PhoneNumbers.Tests/PhoneNumberTests.cs
@@ -166,6 +166,29 @@ public void Parse_Value_With_Custom_ParseOptions()
         Assert.Equal("The value '+441142726444' could not be successfully parsed into a phone number for any country enabled in ParseOptions.", exception.Message);
     }
 
+    [Fact]
+    public void SharesNdcWith()
+    {
+        var phoneNumber1 = TestHelper.CreateGeographicPhoneNumber(
+            trunkPrefix: default,
+            ndc: "12345",
+            sn: "667788");
+
+        var phoneNumber2 = TestHelper.CreateGeographicPhoneNumber(
+            trunkPrefix: default,
+            ndc: "12345",
+            sn: "667788");
+
+        Assert.True(phoneNumber1.SharesNdcWith(phoneNumber2));
+
+        var phoneNumber3 = TestHelper.CreateGeographicPhoneNumber(
+            trunkPrefix: default,
+            ndc: "12346",
+            sn: "667788");
+
+        Assert.False(phoneNumber1.SharesNdcWith(phoneNumber3));
+    }
+
     [Fact]
     public void ToString_Returns_Default_Formatted_PhoneNumber()
     {