Implemented Include Field Match Option. (#167)

Author: nscheibe

src/Snapshooter/Core/MatchOperators/ExcludeMatchOperator.cs

@@ -2,17 +2,29 @@
 
 namespace Snapshooter.Core;
 
+/// <summary>
+/// This field match operator can exclude some specific
+/// fields from a snapshot. The fields will completely be
+/// removed from the snapshot. These excluded fields will
+/// not appear in the snapshot then.
+/// </summary>
 public class ExcludeMatchOperator : FieldMatchOperator
 {
     private readonly string _fieldsPath;
 
+    /// <summary>
+    /// Creates a new instance of the <see cref="ExcludeMatchOperator"/>
+    /// </summary>
+    /// <param name="fieldsPath">The path of the field to exclude.</param>
     public ExcludeMatchOperator(string fieldsPath)
     {
         _fieldsPath = fieldsPath;
     }
 
+    /// <inheritdoc/>
     public override bool HasFormatAction() => true;
 
+    /// <inheritdoc/>
     public override void FormatFields(JToken snapshotData)
     {
         FieldOption fieldOption = new FieldOption(snapshotData);
@@ -23,21 +35,24 @@ public override void FormatFields(JToken snapshotData)
         }
     }
 
+    /// <inheritdoc/>
     public override FieldOption ExecuteMatch(
         JToken snapshotData,
         JToken expectedSnapshotData)
     {
         return new FieldOption(snapshotData);
     }
 
-    private JToken FormatField(JToken field)
+    private static void FormatField(JToken field)
     {
-        if (field.Parent is { } parent)
+        if (field.Parent is JArray array)
+        {
+            array.Remove(field);
+        }
+        else if (field.Parent is { } parent)
         {
             parent.Remove();
         }
-
-        return field;
     }
 }
 

src/Snapshooter/Core/MatchOperators/FieldMatchOperator.cs

@@ -4,12 +4,31 @@
 
 namespace Snapshooter.Core;
 
+/// <summary>
+/// Base class of the match operators.
+/// </summary>
 public abstract class FieldMatchOperator
 {
+    /// <summary>
+    /// Defines if the field match operator will format
+    /// the snapshot.
+    /// </summary>
+    /// <returns>True if the snapshot will be formatted, otherwise False</returns>
     public abstract bool HasFormatAction();
 
+    /// <summary>
+    /// Formats the specified fields of the snapshot.
+    /// </summary>
+    /// <param name="snapshotData">The entire snapshot.</param>
     public abstract void FormatFields(JToken snapshotData);
 
+    /// <summary>
+    /// Compares the specified match fields of the
+    /// current snapshot with the original snapshot.
+    /// </summary>
+    /// <param name="snapshotData">The current snapshot.</param>
+    /// <param name="expectedSnapshotData">The original snapshot.</param>
+    /// <returns></returns>
     public abstract FieldOption ExecuteMatch(
         JToken snapshotData, JToken expectedSnapshotData);
 

src/Snapshooter/Core/MatchOperators/IncludeMatchOperator.cs

@@ -0,0 +1,105 @@
+using System.Collections.Generic;
+using System.Linq;
+using Newtonsoft.Json.Linq;
+
+namespace Snapshooter.Core;
+
+/// <summary>
+/// This field match operator can include some specific
+/// fields of a snapshot. Only the specified fields will
+/// be included within the snapshot. All other fields will
+/// be removed/excluded from the snapshot.
+/// </summary>
+public class IncludeMatchOperator : FieldMatchOperator
+{
+    private readonly List<string> _fieldsPaths;
+
+    /// <summary>
+    /// Creates a new instance of the <see cref="IncludeMatchOperator"/>
+    /// </summary>
+    public IncludeMatchOperator()
+    {
+        _fieldsPaths = new List<string>();
+    }
+
+    /// <inheritdoc/>
+    public override bool HasFormatAction() => true;
+
+    /// <summary>
+    /// Adds a path of a field to include.
+    /// </summary>
+    /// <param name="fieldPath">The path of a field to include.</param>
+    public void AddFieldPath(string fieldPath)
+    {
+        if(!_fieldsPaths.Contains(fieldPath))
+        {
+            _fieldsPaths.Add(fieldPath);
+        }
+    }
+
+    /// <inheritdoc/>
+    public override void FormatFields(JToken snapshotData)
+    {
+        FieldOption fieldOption = new FieldOption(snapshotData);
+
+        List<JToken> includedFields = new List<JToken>();
+
+        foreach(string fieldPath in _fieldsPaths)
+        {
+            List<JToken> fieldsToInclude = fieldOption
+                .FindFieldTokens(fieldPath)
+                .ToList();
+
+            includedFields.AddRange(fieldsToInclude);
+        }
+            
+        FilterIncludedFieldsOnly(snapshotData, includedFields);
+    }
+
+    /// <inheritdoc/>
+    public override FieldOption ExecuteMatch(
+        JToken snapshotData,
+        JToken expectedSnapshotData)
+    {
+        return new FieldOption(snapshotData);
+    }
+
+    private static void FilterIncludedFieldsOnly(
+        JToken snapshotField,
+        List<JToken> includedFields)
+    {
+        foreach (JToken child in snapshotField.Children().ToList())
+        {
+            if (child.HasValues)
+            {
+                if (!includedFields.Any(field =>
+                    child.Path.StartsWith(field.Path) ||
+                    field.Path.StartsWith(child.Path)))
+                {
+                    RemoveField(child);
+
+                    continue;
+                }
+
+                FilterIncludedFieldsOnly(child, includedFields);
+            }
+        }
+    }
+
+    private static void RemoveField(JToken child)
+    {
+        if (child is JProperty property)
+        {
+            property.Remove();
+        }
+        else if (child.Parent is JArray array)
+        {
+            array.Remove(child);
+        }
+        else if (child is JValue value)
+        {
+            value.Parent?.Remove();
+        }
+    }
+}
+

src/Snapshooter/MatchOptions.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Snapshooter.Core;
 using Snapshooter.Exceptions;
 
@@ -474,6 +475,30 @@ public MatchOptions ExcludeField(string fieldPath)
             return this;
         }
 
+        /// <summary>
+        /// The <see cref="IncludeField(string)"/> option includes only the field(s) in a snapshot,
+        /// which have been defined by the fieldPath.
+        /// The field(s) to include is given by the json path <paramref name="fieldPath"/>.
+        /// Only these fields will appear in the snapshot.
+        /// </summary>
+        /// <param name="fieldPath">The json path to the field(s) to include.</param>
+        public MatchOptions IncludeField(string fieldPath)
+        {
+            FieldMatchOperator fieldMatchOperator =
+                _matchOperators.SingleOrDefault(op => op is IncludeMatchOperator);
+
+            if (fieldMatchOperator == null)
+            {
+                fieldMatchOperator = new IncludeMatchOperator();
+                _matchOperators.Add(fieldMatchOperator);
+            }
+
+            var includeMatchOperator = (IncludeMatchOperator)fieldMatchOperator;
+
+            includeMatchOperator.AddFieldPath(fieldPath);
+
+            return this;
+        }
 
         private MatchOptions AddIgnoreMatchOperator<T>(string fieldsPath)
         {

test/Snapshooter.Xunit.Tests/MatchOptions/ExcludeField/ExcludeFieldTests.cs

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using System.Net;
 using FluentAssertions;
 using Snapshooter.Tests.Data;
 using Snapshooter.Xunit.Tests.Helpers;
@@ -159,4 +160,39 @@ public void ExcludeField_ExcludeAllFieldsModified_Mismatch()
         act.Should().Throw<EqualException>()
             .Which.Message.Should().Contain("CountryCode");
     }
+
+    [Fact]
+    public void ExcludeField_DuplicateExcludeFieldsSnapshot_SuccessfullyCompared()
+    {
+        // arrange
+        TestPerson testPerson = TestDataBuilder
+            .TestPersonMarkWalton()
+            .Build();
+
+        // act & assert
+        Snapshot.Match(testPerson, options => options
+            .ExcludeField("Firstname")
+            .ExcludeField("DateOfBirth")
+            .ExcludeField("Size")
+            .ExcludeField("Address.Country.CountryCode")
+            .ExcludeField("Children")
+            .ExcludeField("Relatives[*].Relatives")
+            .ExcludeField("Relatives[*].Address")
+            .ExcludeField("Relatives[*].Address")
+            .ExcludeField("**.Size")
+            .ExcludeField("**.CountryCode"));
+    }
+
+    [Fact]
+    public void ExcludeField_ExcludeArrayFieldSnapshot_SuccessfullyCompared()
+    {
+        // arrange
+        TestPerson testPerson = TestDataBuilder
+            .TestPersonMarkWalton()
+            .Build();
+
+        // act & assert
+        Snapshot.Match(testPerson, options => options
+            .ExcludeField("Children[0]"));
+    }
 }

test/Snapshooter.Xunit.Tests/MatchOptions/ExcludeField/__snapshots__/ExcludeFieldsTests.ExcludeField_DuplicateExcludeFieldsSnapshot_SuccessfullyCompared.snap

@@ -0,0 +1,26 @@
+{
+  "Id": "c78c698f-9ee5-4b4b-9a0e-ef729b1f8ec8",
+  "Lastname": "Walton",
+  "CreationDate": "2018-06-06T00:00:00",
+  "Age": 30,
+  "Address": {
+    "Street": "Rohrstrasse",
+    "StreetNumber": 12,
+    "Plz": 8304,
+    "City": "Wallislellen",
+    "Country": {
+      "Name": "Switzerland"
+    }
+  },
+  "Relatives": [
+    {
+      "Id": "fcf04ca6-d8f2-4214-a3ff-d0ded5bad4de",
+      "Firstname": "Sandra",
+      "Lastname": "Schneider",
+      "CreationDate": "2019-04-01T00:00:00",
+      "DateOfBirth": "1996-02-14T00:00:00",
+      "Age": null,
+      "Children": []
+    }
+  ]
+}

test/Snapshooter.Xunit.Tests/MatchOptions/ExcludeField/__snapshots__/ExcludeFieldsTests.ExcludeField_ExcludeArrayFieldSnapshot_SuccessfullyCompared.snap

@@ -0,0 +1,52 @@
+{
+  "Id": "c78c698f-9ee5-4b4b-9a0e-ef729b1f8ec8",
+  "Firstname": "Mark",
+  "Lastname": "Walton",
+  "CreationDate": "2018-06-06T00:00:00",
+  "DateOfBirth": "2000-06-25T00:00:00",
+  "Age": 30,
+  "Size": 182.5214,
+  "Address": {
+    "Street": "Rohrstrasse",
+    "StreetNumber": 12,
+    "Plz": 8304,
+    "City": "Wallislellen",
+    "Country": {
+      "Name": "Switzerland",
+      "CountryCode": "CH"
+    }
+  },
+  "Children": [
+    {
+      "Name": null,
+      "DateOfBirth": "2015-02-12T00:00:00"
+    },
+    {
+      "Name": "Hanna",
+      "DateOfBirth": "2012-03-20T00:00:00"
+    }
+  ],
+  "Relatives": [
+    {
+      "Id": "fcf04ca6-d8f2-4214-a3ff-d0ded5bad4de",
+      "Firstname": "Sandra",
+      "Lastname": "Schneider",
+      "CreationDate": "2019-04-01T00:00:00",
+      "DateOfBirth": "1996-02-14T00:00:00",
+      "Age": null,
+      "Size": 165.23,
+      "Address": {
+        "Street": "Bahnhofstrasse",
+        "StreetNumber": 450,
+        "Plz": 8000,
+        "City": "Zurich",
+        "Country": {
+          "Name": "Switzerland",
+          "CountryCode": "CH"
+        }
+      },
+      "Children": [],
+      "Relatives": null
+    }
+  ]
+}