JSONReporter considers verbosity when listing tests

* Quiet verbosity provides just the test names
* Normal verbosity adds tags
* High verbosity add the source location of the tests

Listing tests with the quiet verbosity results in about 1/4 of the
previous output, which leads to measurably faster execution of
`catch_discover_tests` when it does not need tags for labels.
(If it does need tags, the output is about 1/2 of previous).

benchmarks/discover_tests/benchmark_discovery.py

@@ -8,6 +8,7 @@
 # SPDX-License-Identifier: BSL-1.0
 
 import argparse
+import copy
 import json
 import os
 import re
@@ -33,14 +34,19 @@ def load_template(path: str) -> dict:
     return catch_out
 
 
-def synthesize_listing(template_doc: dict, count: int, file) -> str:
+def synthesize_listing(template_doc: dict, count: int, file, with_tags: bool) -> str:
     """Writes JSON listing with exactly `count` test cases into `file`.
 
     The template entries are cycled through, and each name is made unique by
     appending an index, so that every registered CTest test has a distinct name.
     """
-    doc_copy = template_doc.copy()
-    template_tests = template_doc['listings']['tests']
+    # To avoid messing up the template tests by deletion, we have
+    # to take a deepcopy before the changes.
+    doc_copy = copy.deepcopy(template_doc)
+    template_tests = doc_copy['listings']['tests']
+    if not with_tags:
+        for test in template_tests:
+            del test['tags']
     num_original = len(template_tests)
 
     out_tests = []
@@ -176,10 +182,10 @@ def main():
         os.makedirs(workdir, exist_ok=True)
         for count in COUNTS:
             listing_path = os.path.join(workdir, f"listing-{count}.json")
-            with open(listing_path, "w", encoding="utf-8") as f:
-                synthesize_listing(template_doc, count, f)
 
             for add_tags in tag_modes:
+                with open(listing_path, "w", encoding="utf-8") as f:
+                    synthesize_listing(template_doc, count, f, add_tags)
                 mode = "on" if add_tags else "off"
                 ctest_file = os.path.join(workdir, f"ctest-{count}-{mode}.cmake")
                 cmd = build_command(args, listing_path, ctest_file, add_tags)

benchmarks/discover_tests/listing_template.json

@@ -11,22 +11,14 @@
         "tags": [
           "function pointer",
           "Tricky"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/UsageTests/Tricky.tests.cpp",
-          "line": 266
-        }
+        ]
       },
       {
         "name": "Testing checked-if 4",
         "tags": [
           "!shouldfail",
           "checked-if"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/UsageTests/Misc.tests.cpp",
-          "line": 216
-        }
+        ]
       },
       {
         "name": "count_equidistant_floats - double",
@@ -34,11 +26,7 @@
           "approvals",
           "distance",
           "floating-point"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/IntrospectiveTests/FloatingPoint.tests.cpp",
-          "line": 103
-        }
+        ]
       },
       {
         "name": "Usage of AllTrue range matcher",
@@ -46,11 +34,7 @@
           "matchers",
           "quantifiers",
           "templated"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/UsageTests/MatchersRanges.tests.cpp",
-          "line": 372
-        }
+        ]
       },
       {
         "name": "Exception matchers that succeed",
@@ -58,11 +42,7 @@
           "!throws",
           "exceptions",
           "matchers"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/UsageTests/Matchers.tests.cpp",
-          "line": 428
-        }
+        ]
       },
       {
         "name": "A TEMPLATE_TEST_CASE_METHOD based test run that succeeds - float",
@@ -70,22 +50,14 @@
         "tags": [
           "class",
           "template"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/UsageTests/Class.tests.cpp",
-          "line": 82
-        }
+        ]
       },
       {
         "name": "Approximate PI",
         "tags": [
           "Approx",
           "PI"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/UsageTests/Approx.tests.cpp",
-          "line": 134
-        }
+        ]
       },
       {
         "name": "TextFlow::Column respects width setting",
@@ -93,32 +65,20 @@
           "approvals",
           "column",
           "TextFlow"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/IntrospectiveTests/TextFlow.tests.cpp",
-          "line": 38
-        }
+        ]
       },
       {
         "name": "Generators internals",
         "tags": [
           "generators",
           "internals"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp",
-          "line": 24
-        }
+        ]
       },
       {
         "name": "Mayfail test case with nested sections",
         "tags": [
           "!mayfail"
-        ],
-        "source-location": {
-          "filename": "/mnt/c/ubuntu/Catch2/tests/SelfTest/UsageTests/Condition.tests.cpp",
-          "line": 83
-        }
+        ]
       }
     ]
   }