basic: Fix broken unit test for IsMissing()

Change-Id: Ia6fb2622c85686a50701d4c37356e608a3df653b
Reviewed-on: https://gerrit.libreoffice.org/37775Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Takeshi Abe <tabe@fixedpoint.jp>

basic/qa/vba_tests/ismissing.vb

@@ -6,7 +6,7 @@ Dim result As String
 
 Function doUnitTest() As String
 result = verify_testIsMissing()
-If failCount <> 0 And passCount > 0 Then
+If failCount <> 0 Or passCount = 0 Then
     doUnitTest = result
 Else
     doUnitTest = "OK"
@@ -23,19 +23,16 @@ Function verify_testIsMissing() As String
     result = "Test Results" & Chr$(10) & "============" & Chr$(10)
 
     Dim testName As String
-    Dim TestDateTime As Date
-    Dim TestStr As String
-    Dim date1, date2
+    Dim num1, num2 As Integer
     testName = "Test IsMissing function"
     On Error GoTo errorHandler
 
-    date2 = Null
-    date1 = ReturnTwice()
-    TestLog_ASSERT IsNull(date1), "the return IsMissing is: " & date1
+    num1 = ReturnTwice()
+    TestLog_ASSERT IsNull(num1)
 
-    date2 = 4
-    date1 = ReturnTwice(2)
-    TestLog_ASSERT date1 = date2, "the return IsMissing is: " & date1
+    num2 = 4
+    num1 = ReturnTwice(2)
+    TestLog_ASSERT num1 = num2, "the return IsMissing is: " & num1
 
     result = result & Chr$(10) & "Tests passed: " & passCount & Chr$(10) & "Tests failed: " & failCount & Chr$(10)
     verify_testIsMissing = result