Add comprehensive tests for X-Axis configuration fix

Co-authored-by: dfinke <67258+dfinke@users.noreply.github.com>

Public/Add-ExcelChart.ps1

@@ -113,6 +113,57 @@ function Add-ExcelChart {
         if ($null -ne $XMinValue) { $chart.XAxis.MinValue = $XMinValue }
         if ($null -ne $XMaxValue) { $chart.XAxis.MaxValue = $XMaxValue }
         if ($XAxisNumberformat) { $chart.XAxis.Format = (Expand-NumberFormat $XAxisNumberformat) }
+        
+        # Fix for category axis (used in line charts, etc.): EPPlus doesn't serialize MajorUnit/MinorUnit to XML for category axes
+        # We need to manually add these elements to the XML if they were specified
+        if ($XMajorUnit -or $XMinorUnit) {
+            $chartXml = $chart.ChartXml
+            $nsManager = New-Object System.Xml.XmlNamespaceManager($chartXml.NameTable)
+            $null = $nsManager.AddNamespace("c", "http://schemas.openxmlformats.org/drawingml/2006/chart")
+            $catAx = $chartXml.SelectSingleNode("//c:catAx", $nsManager)
+            
+            if ($catAx) {
+                # Category axis exists - need to add majorUnit/minorUnit elements
+                if ($XMajorUnit) {
+                    $existingMajorUnit = $catAx.SelectSingleNode("c:majorUnit", $nsManager)
+                    if (-not $existingMajorUnit) {
+                        $majorUnitElement = $chartXml.CreateElement("c", "majorUnit", "http://schemas.openxmlformats.org/drawingml/2006/chart")
+                        $null = $majorUnitElement.SetAttribute("val", $XMajorUnit)
+                        # Insert after scaling element or at the beginning
+                        $scalingNode = $catAx.SelectSingleNode("c:scaling", $nsManager)
+                        if ($scalingNode) {
+                            $null = $catAx.InsertAfter($majorUnitElement, $scalingNode)
+                        } else {
+                            $null = $catAx.PrependChild($majorUnitElement)
+                        }
+                    } else {
+                        $null = $existingMajorUnit.SetAttribute("val", $XMajorUnit)
+                    }
+                }
+                
+                if ($XMinorUnit) {
+                    $existingMinorUnit = $catAx.SelectSingleNode("c:minorUnit", $nsManager)
+                    if (-not $existingMinorUnit) {
+                        $minorUnitElement = $chartXml.CreateElement("c", "minorUnit", "http://schemas.openxmlformats.org/drawingml/2006/chart")
+                        $null = $minorUnitElement.SetAttribute("val", $XMinorUnit)
+                        # Insert after majorUnit if it exists, otherwise after scaling
+                        $majorUnitNode = $catAx.SelectSingleNode("c:majorUnit", $nsManager)
+                        if ($majorUnitNode) {
+                            $null = $catAx.InsertAfter($minorUnitElement, $majorUnitNode)
+                        } else {
+                            $scalingNode = $catAx.SelectSingleNode("c:scaling", $nsManager)
+                            if ($scalingNode) {
+                                $null = $catAx.InsertAfter($minorUnitElement, $scalingNode)
+                            } else {
+                                $null = $catAx.PrependChild($minorUnitElement)
+                            }
+                        }
+                    } else {
+                        $null = $existingMinorUnit.SetAttribute("val", $XMinorUnit)
+                    }
+                }
+            }
+        }
 
         if ($YAxisTitleText) {
             $chart.YAxis.Title.Text = $YAxisTitleText

__tests__/Add-ExcelChart-XAxis.Tests.ps1

@@ -0,0 +1,135 @@
+# Test for X-Axis configuration on line charts
+# This test verifies that XMajorUnit and XMinorUnit parameters work correctly for line charts
+
+Describe "X-Axis Configuration for Line Charts" {
+    BeforeAll {
+        $path = "TestDrive:\xaxis_test.xlsx"
+    }
+
+    Context "X-Axis MajorUnit and MinorUnit on Line Charts" {
+        BeforeAll {
+            # Create test data
+            $excel = 1..7 | ForEach-Object { 
+                [pscustomobject][ordered]@{
+                    XValue = @(5, 10, 15, 20, 25, 30, 35)[$_ - 1]
+                    YValue = @(18, 11, 23, 17, 12, 32, 12)[$_ - 1]
+                } 
+            } | Export-Excel -Path $path -WorksheetName "Test" -PassThru -AutoNameRange
+            
+            # Add chart with X-axis configuration
+            Add-ExcelChart -Worksheet $excel.Workbook.Worksheets["Test"] `
+                -ChartType Line `
+                -XRange "XValue" `
+                -YRange "YValue" `
+                -Title "Test Chart" `
+                -XMinValue 0 `
+                -XMaxValue 40 `
+                -XMajorUnit 10 `
+                -XMinorUnit 5 `
+                -YMinValue 0 `
+                -YMaxValue 40 `
+                -YMajorUnit 10 `
+                -YMinorUnit 5
+            
+            Close-ExcelPackage $excel
+            
+            # Reopen to verify
+            $excel = Open-ExcelPackage -Path $path
+            $ws = $excel.Workbook.Worksheets["Test"]
+            $chart = $ws.Drawings[0]
+        }
+        
+        It "Set XAxis.MinValue correctly" {
+            $chart.XAxis.MinValue | Should -Be 0
+        }
+        
+        It "Set XAxis.MaxValue correctly" {
+            $chart.XAxis.MaxValue | Should -Be 40
+        }
+        
+        It "Set XAxis.MajorUnit correctly" {
+            $chart.XAxis.MajorUnit | Should -Be 10
+        }
+        
+        It "Set XAxis.MinorUnit correctly" {
+            $chart.XAxis.MinorUnit | Should -Be 5
+        }
+        
+        It "Added MajorUnit to category axis XML" {
+            $xml = $chart.ChartXml
+            $nsmgr = New-Object System.Xml.XmlNamespaceManager($xml.NameTable)
+            $nsmgr.AddNamespace("c", "http://schemas.openxmlformats.org/drawingml/2006/chart")
+            $catAx = $xml.SelectSingleNode("//c:catAx", $nsmgr)
+            $majorUnit = $catAx.SelectSingleNode("c:majorUnit", $nsmgr)
+            
+            $majorUnit | Should -Not -BeNullOrEmpty
+            $majorUnit.val | Should -Be "10"
+        }
+        
+        It "Added MinorUnit to category axis XML" {
+            $xml = $chart.ChartXml
+            $nsmgr = New-Object System.Xml.XmlNamespaceManager($xml.NameTable)
+            $nsmgr.AddNamespace("c", "http://schemas.openxmlformats.org/drawingml/2006/chart")
+            $catAx = $xml.SelectSingleNode("//c:catAx", $nsmgr)
+            $minorUnit = $catAx.SelectSingleNode("c:minorUnit", $nsmgr)
+            
+            $minorUnit | Should -Not -BeNullOrEmpty
+            $minorUnit.val | Should -Be "5"
+        }
+        
+        AfterAll {
+            Close-ExcelPackage $excel -NoSave
+        }
+    }
+    
+    Context "X-Axis without MajorUnit and MinorUnit" {
+        BeforeAll {
+            $path2 = "TestDrive:\xaxis_test2.xlsx"
+            # Create test data without X-axis units
+            $excel2 = 1..7 | ForEach-Object { 
+                [pscustomobject][ordered]@{
+                    XValue = @(5, 10, 15, 20, 25, 30, 35)[$_ - 1]
+                    YValue = @(18, 11, 23, 17, 12, 32, 12)[$_ - 1]
+                } 
+            } | Export-Excel -Path $path2 -WorksheetName "Test" -PassThru -AutoNameRange
+            
+            # Add chart WITHOUT X-axis MajorUnit/MinorUnit
+            Add-ExcelChart -Worksheet $excel2.Workbook.Worksheets["Test"] `
+                -ChartType Line `
+                -XRange "XValue" `
+                -YRange "YValue" `
+                -Title "Test Chart"
+            
+            Close-ExcelPackage $excel2
+            
+            # Reopen to verify
+            $excel2 = Open-ExcelPackage -Path $path2
+            $ws2 = $excel2.Workbook.Worksheets["Test"]
+            $chart2 = $ws2.Drawings[0]
+        }
+        
+        It "Should not add MajorUnit to category axis XML when not specified" {
+            $xml = $chart2.ChartXml
+            $nsmgr = New-Object System.Xml.XmlNamespaceManager($xml.NameTable)
+            $nsmgr.AddNamespace("c", "http://schemas.openxmlformats.org/drawingml/2006/chart")
+            $catAx = $xml.SelectSingleNode("//c:catAx", $nsmgr)
+            $majorUnit = $catAx.SelectSingleNode("c:majorUnit", $nsmgr)
+            
+            $majorUnit | Should -BeNullOrEmpty
+        }
+        
+        It "Should not add MinorUnit to category axis XML when not specified" {
+            $xml = $chart2.ChartXml
+            $nsmgr = New-Object System.Xml.XmlNamespaceManager($xml.NameTable)
+            $nsmgr.AddNamespace("c", "http://schemas.openxmlformats.org/drawingml/2006/chart")
+            $catAx = $xml.SelectSingleNode("//c:catAx", $nsmgr)
+            $minorUnit = $catAx.SelectSingleNode("c:minorUnit", $nsmgr)
+            
+            $minorUnit | Should -BeNullOrEmpty
+        }
+        
+        AfterAll {
+            Close-ExcelPackage $excel2 -NoSave
+        }
+    }
+}