measurestack: Allow output groups to be empty

2 files changed, 56 insertions, 2 deletions

diff --git a/build-aux/measurestack/app_output.py b/build-aux/measurestack/app_output.py
index b220101..5336b85 100644
--- a/build-aux/measurestack/app_output.py
+++ b/build-aux/measurestack/app_output.py
@@ -20,6 +20,9 @@ def print_group(
     grp_name: str,
 ) -> None:
     grp = result.groups[grp_name]
+    if not grp.rows:
+        print(f"= {grp_name} (empty) =")
+        return
 
     nsum = sum(v.nstatic * v.cnt for v in grp.rows.values())
     nmax = max(v.nstatic for v in grp.rows.values())
@@ -130,8 +133,7 @@ def print_c(
     print("*/")
     print("")
     print("/*")
-    if result.groups["Extra"].rows:
-        print_group(result, location_xform, "Extra")
+    print_group(result, location_xform, "Extra")
     for funcname in sorted(result.included_funcs):
         print(f"included: {location_xform(funcname)}")
     print("*/")
diff --git a/build-aux/measurestack/test_app_output.py b/build-aux/measurestack/test_app_output.py
new file mode 100644
index 0000000..4653d4e
--- /dev/null
+++ b/build-aux/measurestack/test_app_output.py
@@ -0,0 +1,52 @@
+# build-aux/measurestack/test_app_output.py - Tests for app_output.py
+#
+# Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+# pylint: disable=unused-variable
+
+import contextlib
+import io
+
+from . import analyze, app_output
+
+
+def test_print_group() -> None:
+    result = analyze.AnalyzeResult(
+        groups={
+            "A": analyze.AnalyzeResultGroup(
+                rows={
+                    analyze.QName("short"): analyze.AnalyzeResultVal(nstatic=8, cnt=1),
+                    analyze.QName(
+                        "anamethatisnttoolongbutisnttooshort"
+                    ): analyze.AnalyzeResultVal(nstatic=9, cnt=2),
+                }
+            ),
+            "B": analyze.AnalyzeResultGroup(rows={}),
+        },
+        missing=set(),
+        dynamic=set(),
+        included_funcs=set(),
+    )
+
+    def location_xform(loc: analyze.QName) -> str:
+        return str(loc)
+
+    stdout = io.StringIO()
+    with contextlib.redirect_stdout(stdout):
+        print()
+        app_output.print_group(result, location_xform, "A")
+        app_output.print_group(result, location_xform, "B")
+    assert (
+        stdout.getvalue()
+        == """
+= A =============================== ==
+anamethatisnttoolongbutisnttooshort  9 * 2
+short                                8
+----------------------------------- --
+Total                               26
+Maximum                              9
+=================================== ==
+= B (empty) =
+"""
+    )