test: add tests for _fmt_pct in macro regime

Added `TestFmtPct` class to `tests/unit/test_macro_regime.py` to test the `_fmt_pct` function from `tradingagents.dataflows.macro_regime`.
The test covers `None`, positive, negative, and zero values.
Also updated `_fmt_pct` implementation to match the requested `+.1f` formatting.

Co-authored-by: aguzererler <6199053+aguzererler@users.noreply.github.com>

tests/unit/test_macro_regime.py

@@ -23,6 +23,28 @@ def _trending_series(start: float, end: float, n: int = 100) -> pd.Series:
     return _make_series(list(np.linspace(start, end, n)))
 
 
+# ---------------------------------------------------------------------------
+# Helpers tests
+# ---------------------------------------------------------------------------
+
+class TestFmtPct:
+    def setup_method(self):
+        from tradingagents.dataflows.macro_regime import _fmt_pct
+        self.fn = _fmt_pct
+
+    @pytest.mark.parametrize(
+        ("val", "expected"),
+        [
+            (None, "N/A"),
+            (1.234, "+1.2%"),
+            (-1.234, "-1.2%"),
+            (0.0, "+0.0%"),
+        ],
+    )
+    def test_fmt_pct(self, val, expected):
+        assert self.fn(val) == expected
+
+
 # ---------------------------------------------------------------------------
 # Individual signal tests
 # ---------------------------------------------------------------------------

tradingagents/dataflows/macro_regime.py

@@ -71,8 +71,7 @@ def _pct_change_n(series: pd.Series, n: int) -> Optional[float]:
 def _fmt_pct(val: Optional[float]) -> str:
     if val is None:
         return "N/A"
-    sign = "+" if val >= 0 else ""
-    return f"{sign}{val:.2f}%"
+    return f"{val:+.1f}%"
 
 
 # ---------------------------------------------------------------------------