Add fuzzing tests for go 1.18 to fix scrolling edge cases

.gitignore

@@ -13,6 +13,9 @@
 *.out
 *.coverage
 
+# Fuzzing data
+testdata
+
 # Go vendor folder
 vendor/
 

table/scrolling.go

@@ -47,10 +47,4 @@ func (m *Model) recalculateLastHorizontalColumn() {
 			m.maxHorizontalColumnIndex = i - m.horizontalScrollFreezeColumnsCount
 		}
 	}
-
-	if m.maxHorizontalColumnIndex <= m.horizontalScrollFreezeColumnsCount {
-		m.maxHorizontalColumnIndex = 0
-
-		return
-	}
 }

table/scrolling_fuzz_test.go

@@ -0,0 +1,96 @@
+//go:build go1.18
+// +build go1.18
+
+package table
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/stretchr/testify/assert"
+)
+
+// This is long because of test cases
+// nolint: funlen
+func FuzzHorizontalScrollingStopEdgeCases(f *testing.F) {
+	const (
+		minNameWidth = 2
+		maxNameWidth = 50
+
+		minColWidth = 4
+		maxColWidth = 50
+
+		minNumCols = 1
+		maxNumCols = 500
+
+		minMaxWidth = 5
+		maxMaxWidth = 200
+
+		borderBuffer = 4
+	)
+
+	f.Add(5, 3, 5, 30)
+	f.Fuzz(func(t *testing.T, nameWidth, colWidth, numCols, maxWidth int) {
+		if nameWidth < minNameWidth ||
+			nameWidth > maxNameWidth ||
+			nameWidth > maxWidth-colWidth ||
+			nameWidth+colWidth+borderBuffer >= maxWidth {
+			return
+		}
+
+		if colWidth < minColWidth ||
+			colWidth > maxColWidth ||
+			colWidth >= maxWidth {
+			return
+		}
+
+		if numCols < minNumCols || numCols > maxNumCols {
+			return
+		}
+
+		if maxWidth < minMaxWidth || maxWidth > maxMaxWidth {
+			return
+		}
+
+		cols := []Column{NewColumn("Name", "Name", nameWidth)}
+		for i := 0; i < numCols; i++ {
+			s := fmt.Sprintf("%d", i+1)
+			cols = append(cols, NewColumn(s, s, colWidth))
+		}
+
+		rowData := RowData{"Name": "A"}
+
+		for i := 0; i < numCols; i++ {
+			s := fmt.Sprintf("%d", i+1)
+			rowData[s] = s
+		}
+
+		rows := []Row{NewRow(rowData)}
+
+		model := New(cols).
+			WithRows(rows).
+			WithStaticFooter("Footer").
+			WithMaxTotalWidth(maxWidth).
+			WithHorizontalFreezeColumnCount(1).
+			Focused(true)
+
+		hitScrollRight := func() {
+			model, _ = model.Update(tea.KeyMsg{Type: tea.KeyShiftRight})
+		}
+
+		// Excessive scrolling attempts to be sure
+		for i := 0; i < numCols*2; i++ {
+			hitScrollRight()
+		}
+
+		rendered := model.View()
+
+		assert.NotContains(t, rendered, ">")
+
+		if !strings.Contains(rendered, "…") {
+			assert.Contains(t, rendered, fmt.Sprintf("%d", numCols))
+		}
+	})
+}

table/scrolling_test.go

@@ -307,6 +307,18 @@ func TestHorizontalScrollingStopEdgeCases(t *testing.T) {
 			maxWidth:     20,
 			expectedCols: []int{7, 8},
 		},
+		{
+			numCols:      6,
+			nameWidth:    5,
+			colWidth:     3,
+			maxWidth:     30,
+		},
+		{
+			numCols:      50,
+			nameWidth:    20,
+			colWidth:     6,
+			maxWidth:     31,
+		},
 	}
 
 	for i, test := range tests {