test: Exclude parts of code from coverage calculation

Exclude several sections of code from coverage calculation.  These
sections contain code that is repetitive or which is related to
debugging.

httpstan/build_ext.py

@@ -19,7 +19,7 @@
 
 
 def _get_build_extension() -> distutils.command.build_ext.build_ext:  # type: ignore
-    if HTTPSTAN_DEBUG:
+    if HTTPSTAN_DEBUG:  # pragma: no cover
         distutils.log.set_verbosity(distutils.log.DEBUG)  # type: ignore
     dist = distutils.core.Distribution()
     # Make sure build respects distutils configuration
@@ -47,7 +47,7 @@ def _has_fileno(stream: TextIO) -> bool:
         """
         try:
             stream.fileno()
-        except (AttributeError, OSError, IOError, io.UnsupportedOperation):
+        except (AttributeError, OSError, IOError, io.UnsupportedOperation):  # pragma: no cover
             return False
         return True
 

httpstan/services_stub.py

@@ -33,7 +33,7 @@
 # because `pickle` (used by ProcessPoolExecutor) cannot pickle local functions.
 def _make_lazy_function_wrapper_helper(
     function_basename: str, model_name: str, *args: typing.Any, **kwargs: typing.Any
-) -> typing.Callable:
+) -> typing.Callable:  # pragma: no cover
     services_module = httpstan.models.import_services_extension_module(model_name)
     function = getattr(services_module, function_basename + "_wrapper")
     return function(*args, **kwargs)  # type: ignore
@@ -94,7 +94,7 @@ async def call(
         lazy_function_wrapper_partial = functools.partial(lazy_function_wrapper, socket_filename, **kwargs)
 
         # If HTTPSTAN_DEBUG is set block until sampling is complete. Do not use an executor.
-        if HTTPSTAN_DEBUG:
+        if HTTPSTAN_DEBUG:  # pragma: no cover
             future: asyncio.Future = asyncio.Future()
             logger.debug("Calling stan::services function with debug mode on.")
             print("Warning: httpstan debug mode is on! `num_samples` must be set to a small number (e.g., 10).")

httpstan/views.py

@@ -188,7 +188,7 @@ async def handle_delete_model(request: aiohttp.web.Request) -> aiohttp.web.Respo
 
     try:
         httpstan.models.import_services_extension_module(model_name)
-    except KeyError:
+    except KeyError:  # pragma: no cover
         message, status = f"Model `{model_name}` not found.", 404
         return aiohttp.web.json_response(_make_error(message, status=status), status=status)
 
@@ -251,7 +251,7 @@ async def handle_show_params(request: aiohttp.web.Request) -> aiohttp.web.Respon
 
     try:
         services_module = httpstan.models.import_services_extension_module(model_name)
-    except KeyError:
+    except KeyError:  # pragma: no cover
         message, status = f"Model `{model_name}` not found.", 404
         return aiohttp.web.json_response(_make_error(message, status=status), status=status)
 
@@ -342,7 +342,7 @@ async def handle_create_fit(request: aiohttp.web.Request) -> aiohttp.web.Respons
 
     try:
         httpstan.models.import_services_extension_module(model_name)
-    except KeyError:
+    except KeyError:  # pragma: no cover
         message, status = f"Model `{model_name}` not found.", 404
         return aiohttp.web.json_response(_make_error(message, status=status), status=status)
 
@@ -453,7 +453,7 @@ async def handle_get_fit(request: aiohttp.web.Request) -> aiohttp.web.Response:
 
     try:
         fit_bytes_lz4 = httpstan.cache.load_fit(fit_name)
-    except KeyError:
+    except KeyError:  # pragma: no cover
         message, status = f"Fit `{fit_name}` not found.", 404
         return aiohttp.web.json_response(_make_error(message, status=status), status=status)
     fit_bytes = lz4.frame.decompress(fit_bytes_lz4)
@@ -495,7 +495,7 @@ async def handle_delete_fit(request: aiohttp.web.Request) -> aiohttp.web.Respons
 
     try:
         httpstan.cache.load_fit(fit_name)
-    except KeyError:
+    except KeyError:  # pragma: no cover
         message, status = f"Fit `{fit_name}` not found.", 404
         return aiohttp.web.json_response(_make_error(message, status=status), status=status)
 
@@ -554,7 +554,7 @@ async def handle_get_operation(request: aiohttp.web.Request) -> aiohttp.web.Resp
     operation_name = f"operations/{request.match_info['operation_id']}"
     try:
         operation = request.app["operations"][operation_name]
-    except KeyError:
+    except KeyError:  # pragma: no cover
         message, status = f"Operation `{operation_name}` not found.", 404
         return aiohttp.web.json_response(_make_error(message, status=status), status=status)
     return aiohttp.web.json_response(operation)