Add unit test for table behaviour

Signed-off-by: Edward McFarlane <emcfarlane@buf.build>

internal/descriptor/table_test.go

@@ -0,0 +1,86 @@
+package descriptor
+
+import (
+	"testing"
+
+	"github.com/tetratelabs/wazero/internal/testing/require"
+)
+
+func Test_sizeOfTable(t *testing.T) {
+	tests := []struct {
+		name         string
+		operation    func(*Table[int32, string])
+		expectedSize int
+	}{
+		{
+			name:         "empty table",
+			operation:    func(table *Table[int32, string]) {},
+			expectedSize: 0,
+		},
+		{
+			name: "1 insert",
+			operation: func(table *Table[int32, string]) {
+				table.Insert("a")
+			},
+			expectedSize: 1,
+		},
+		{
+			name: "32 inserts",
+			operation: func(table *Table[int32, string]) {
+				for i := 0; i < 32; i++ {
+					table.Insert("a")
+				}
+			},
+			expectedSize: 1,
+		},
+		{
+			name: "257 inserts",
+			operation: func(table *Table[int32, string]) {
+				for i := 0; i < 257; i++ {
+					table.Insert("a")
+				}
+			},
+			expectedSize: 5,
+		},
+		{
+			name: "1 insert at 63",
+			operation: func(table *Table[int32, string]) {
+				table.InsertAt("a", 63)
+			},
+			expectedSize: 1,
+		},
+		{
+			name: "1 insert at 64",
+			operation: func(table *Table[int32, string]) {
+				table.InsertAt("a", 64)
+			},
+			expectedSize: 2,
+		},
+		{
+			name: "1 insert at 257",
+			operation: func(table *Table[int32, string]) {
+				table.InsertAt("a", 257)
+			},
+			expectedSize: 5,
+		},
+		{
+			name: "insert at until 320",
+			operation: func(table *Table[int32, string]) {
+				for i := int32(0); i < 320; i++ {
+					table.InsertAt("a", i)
+				}
+			},
+			expectedSize: 5,
+		},
+	}
+	for _, tt := range tests {
+		tc := tt
+
+		t.Run(tc.name, func(t *testing.T) {
+			table := new(Table[int32, string])
+			tc.operation(table)
+			require.Equal(t, tc.expectedSize, len(table.masks))
+			require.Equal(t, tc.expectedSize*64, len(table.items))
+		})
+	}
+}