Fixed some query result output formatting issues

Author: YuriyIvon

src/DatabaseBenchmark/Common/LightweightDataRow.cs

@@ -6,7 +6,7 @@ public class LightweightDataRow
 
         public object this[string columnName]
         {
-            get => _columnValues[columnName];
+            get => _columnValues.GetValueOrDefault(columnName);
             set => _columnValues[columnName] = value;
         }
 

src/DatabaseBenchmark/Core/ValueFormatter.cs

@@ -9,11 +9,12 @@ public class ValueFormatter : IValueFormatter
         public string Format(object value) =>
             value switch
             {
+                null => "NULL",
                 string => $"\"{value}\"",
                 IEnumerable arrayValue => $"[{string.Join(", ", arrayValue.Cast<object>().Select(Format))}]",
                 DateTime dateTimeValue => dateTimeValue.ToSortableString(), // TODO: Make output date/time format configurable
                 DateTimeOffset dateTimeOffsetValue => dateTimeOffsetValue.ToSortableString(), // TODO: Make output date/time format configurable
-                double or float => string.Format($"{value:0.##}"), // TODO: Make precision configurable
+                double or float or decimal => string.Format($"{value:0.##}"), // TODO: Make precision configurable
                 bool boolValue => boolValue.ToString(),
                 _ when value.IsNumber() => value.ToString(),
                 _ => $"\"{value}\"" // TODO: Make quotemarks configurable

src/DatabaseBenchmark/Reporting/TextTableReportFormatter.cs

@@ -15,7 +15,7 @@ public TextTableReportFormatter(IValueFormatter valueFormatter)
 
         public void Print(Stream stream, LightweightDataTable results)
         {
-            using var writer = new StreamWriter(stream);
+            using var writer = new StreamWriter(stream, leaveOpen: true);
 
             foreach (var column in results.Columns)
             {

tests/DatabaseBenchmark.Tests/Core/ValueFormatterTests.cs

@@ -19,14 +19,15 @@ public class ValueFormatterTests
             [(long)123, "123"],
             [(float)1.2345, "1.23"],
             [(double)1.2345, "1.23"],
-            [(decimal)1.2345, "1.2345"],
+            [(decimal)1.2345, "1.23"],
             [true, "True"],
             ["abc", "\"abc\""],
             [new Guid("6971bc34-4117-4dba-a405-d2ffa82bf6d2"), "\"6971bc34-4117-4dba-a405-d2ffa82bf6d2\""],
             [new string[] {"one", "two", "three"}, "[\"one\", \"two\", \"three\"]"],
             [new double[] {1.765, 12.351}, "[1.77, 12.35]"],
             [new DateTime(2023, 12, 11), "2023-12-11T00:00:00.0000000"],
-            [new DateTime(2023, 12, 11, 1, 2, 3), "2023-12-11T01:02:03.0000000"]
+            [new DateTime(2023, 12, 11, 1, 2, 3), "2023-12-11T01:02:03.0000000"],
+            [null, "NULL"]
         ];
 
         [Theory]

tests/DatabaseBenchmark.Tests/Reporting/TextTableReportFormatterTests.cs

@@ -0,0 +1,55 @@
+using DatabaseBenchmark.Common;
+using DatabaseBenchmark.Core;
+using DatabaseBenchmark.Reporting;
+using System;
+using System.IO;
+using Xunit;
+
+namespace DatabaseBenchmark.Tests.Reporting
+{
+    public class TextTableReportFormatterTests
+    {
+        private const string NameColumn = "Name";
+        private const string CountColumn = "Count";
+        private const string OptionalColumn = "Optional";
+
+        private readonly LightweightDataTable _sampleResults;
+
+        public TextTableReportFormatterTests()
+        {
+            _sampleResults = new LightweightDataTable();
+            _sampleResults.Columns.Add(new LightweightDataColumn(NameColumn, _sampleResults));
+            _sampleResults.Columns.Add(new LightweightDataColumn(CountColumn, _sampleResults));
+            _sampleResults.Columns.Add(new LightweightDataColumn(OptionalColumn, _sampleResults));
+            var row = _sampleResults.AddRow();
+            row[NameColumn] = "Regular row";
+            row[CountColumn] = 1;
+            row = _sampleResults.AddRow();
+            row[NameColumn] = "Optional attribute row";
+            row[CountColumn] = 12;
+            row[OptionalColumn] = 123.4567;
+        }
+
+        [Fact]
+        public void PrintTable()
+        {
+            var tableFormatter = new TextTableReportFormatter(new ValueFormatter());
+            using var stream = new MemoryStream();
+
+            tableFormatter.Print(stream, _sampleResults);
+
+            stream.Seek(0, SeekOrigin.Begin);
+            using var reader = new StreamReader(stream);
+            var result = reader.ReadToEnd();
+
+            var expectedText = "+------------------------+-----+--------+" + Environment.NewLine +
+                               "|                    Name|Count|Optional|" + Environment.NewLine +
+                               "+------------------------+-----+--------+" + Environment.NewLine +
+                               "|\"Regular row\"           |    1|NULL    |" + Environment.NewLine +
+                               "|\"Optional attribute row\"|   12|  123.46|" + Environment.NewLine +
+                               "+------------------------+-----+--------+" + Environment.NewLine + Environment.NewLine;
+
+            Assert.Equal(expectedText, result);
+        }
+    }
+}