models/tests: Enforce logo_opacity > 0 and update validation tests

- Updated `_PdfSignatureConfigurationModel` to set `logo_opacity` lower
  bound as strictly greater than 0 (`gt=0`) instead of greater than or
  equal to 0 (`ge=0`).
- Modified `test_sign_pdf.py` to reflect the updated constraint:
  - Adjusted parametrized tests to replace 0.0 with 0.01 for minimum
    valid opacity.
  - Added test case for 0.0 as an invalid opacity value.
  - Updated validation error match regex to account for the new rule.

Assisted-by: Codex

Author: datalogics-kam

src/pdfrest/models/_internal.py

@@ -985,7 +985,7 @@ class _PdfSignatureDisplayModel(BaseModel):
 class _PdfSignatureConfigurationModel(BaseModel):
     type: Literal["new", "existing"]
     name: str | None = None
-    logo_opacity: Annotated[float | None, Field(ge=0, le=1, default=None)] = None
+    logo_opacity: Annotated[float | None, Field(gt=0, le=1, default=None)] = None
     location: _PdfSignatureLocationModel | None = None
     display: _PdfSignatureDisplayModel | None = None
 

tests/test_sign_pdf.py

@@ -707,7 +707,7 @@ def test_sign_payload_accepts_logo_tuple_sequence() -> None:
 @pytest.mark.parametrize(
     "logo_opacity",
     [
-        pytest.param(0.0, id="min"),
+        pytest.param(0.01, id="min"),
         pytest.param(1.0, id="max"),
     ],
 )
@@ -735,6 +735,7 @@ def test_sign_payload_accepts_logo_opacity_bounds(logo_opacity: float) -> None:
 @pytest.mark.parametrize(
     "invalid_logo_opacity",
     [
+        pytest.param(0.0, id="zero"),
         pytest.param(-0.01, id="below-min"),
         pytest.param(1.01, id="above-max"),
     ],
@@ -748,7 +749,7 @@ def test_sign_payload_rejects_logo_opacity_out_of_bounds(
 
     with pytest.raises(
         ValidationError,
-        match=r"greater than or equal to 0|less than or equal to 1",
+        match=r"greater than 0|less than or equal to 1",
     ):
         PdfSignPayload.model_validate(
             {