correct the formatting for positive numbers with negative exponents and add additional test

Author: adrianmolzon

bayes_opt/logger.py

@@ -82,7 +82,7 @@ def _format_number(self, x: float) -> str:
             result = ""
             width = self._default_cell_size
             # Keep negative sign, exponent, and as many decimal places as possible
-            if "-" in s:
+            if x < 0:
                 result += "-"
                 width -= 1
                 s = s[1:]

tests/test_logger.py

@@ -87,6 +87,10 @@ def test_format_number():
     assert len(formatted) == logger._default_cell_size
     assert formatted == "1.234e+13"
 
+    sci_float = 1.11111111e-5
+    formatted = logger._format_number(sci_float)
+    assert formatted == "1.111e-05"
+
     # Test negative scientific notation truncation
     sci_float = -12345678901234.5678901234
     formatted = logger._format_number(sci_float)