fix(test): explicitly require members in xpath query assertion

test/workbook/worksheet/tc_cell.rb

@@ -294,7 +294,7 @@ def test_to_xml_string_with_run
  @c.font_name = 'arial'
  @c.color = 'FF0000'
  c_xml = Nokogiri::XML(@c.to_xml_string(1,1))
- assert(c_xml.xpath("//b"))
+ assert(c_xml.xpath("//b").any?)
  end
 
  def test_to_xml_string_formula
@@ -303,8 +303,8 @@ def test_to_xml_string_formula
  sheet.add_row ["=IF(2+2=4,4,5)"]
  end
  doc = Nokogiri::XML(ws.to_xml_string)
- assert(doc.xpath("//f[@text()='IF(2+2=4,4,5)']"))
-
+ doc.remove_namespaces!
+ assert(doc.xpath("//f[text()='IF(2+2=4,4,5)']").any?)
  end
 
  def test_to_xml_string_array_formula
@@ -314,9 +314,9 @@ def test_to_xml_string_array_formula
  end
  doc = Nokogiri::XML(ws.to_xml_string)
  doc.remove_namespaces!
- assert(doc.xpath("//f[text()='SUM(C2:C11*D2:D11)']"))
- assert(doc.xpath("//f[@t='array']"))
- assert(doc.xpath("//f[@ref='A1']"))
+ assert(doc.xpath("//f[text()='SUM(C2:C11*D2:D11)']").any?)
+ assert(doc.xpath("//f[@t='array']").any?)
+ assert(doc.xpath("//f[@ref='A1']").any?)
  end
 
  def test_to_xml_string_text_formula