[grohtml]: Fix Savannah #63824 (1/2).

[grohtml]: Revise tests to check for requisite programs at test time and
skip if not found, rather than configuring them away at build time,
which can cause a distribution archive to be incorrectly structured.

* m4/groff.m4: Annotate requisite program list since we're violating the
  DRY principle.

* src/roff/groff/groff.am (groff_TESTS): Populate unconditionally.

* src/roff/groff/tests/html_works_with_grn_and_eqn.sh:
* src/roff/groff/tests/smoke-test_html_device.sh: Check for requisite
  programs and skip test if any are not found.

Fixes <https://savannah.gnu.org/bugs/?63824> (1/2).

3 files changed, 24 insertions, 4 deletions

diff --git a/src/roff/groff/groff.am b/src/roff/groff/groff.am
index 82cb03760..8937d4ced 100644
--- a/src/roff/groff/groff.am
+++ b/src/roff/groff/groff.am
@@ -47,6 +47,7 @@ groff_TESTS = \
   src/roff/groff/tests/evc_produces_no_output_if_invalid.sh \
   src/roff/groff/tests/fp_should_not_traverse_directories.sh \
   src/roff/groff/tests/handle_special_input_code_points.sh \
+  src/roff/groff/tests/html_works_with_grn_and_eqn.sh \
   src/roff/groff/tests/initialization_is_quiet.sh \
   src/roff/groff/tests/localization_works.sh \
   src/roff/groff/tests/msoquiet_works.sh \
@@ -58,6 +59,7 @@ groff_TESTS = \
   src/roff/groff/tests/regression_savannah_58162.sh \
   src/roff/groff/tests/regression_savannah_58337.sh \
   src/roff/groff/tests/regression_savannah_59202.sh \
+  src/roff/groff/tests/smoke-test_html_device.sh \
   src/roff/groff/tests/some_escapes_accept_newline_delimiters.sh \
   src/roff/groff/tests/soquiet_works.sh \
   src/roff/groff/tests/string_case_xform_errors.sh \
@@ -65,10 +67,6 @@ groff_TESTS = \
   src/roff/groff/tests/string_case_xform_unicode_escape.sh \
   src/roff/groff/tests/substring_works.sh \
   src/roff/groff/tests/use_point_size_escape_with_single_digit_arg.sh
-if USE_GROHTML
-groff_TESTS += src/roff/groff/tests/html_works_with_grn_and_eqn.sh \
-  src/roff/groff/tests/smoke-test_html_device.sh
-endif
 TESTS += $(groff_TESTS)
 EXTRA_DIST += $(groff_TESTS)
 
diff --git a/src/roff/groff/tests/html_works_with_grn_and_eqn.sh b/src/roff/groff/tests/html_works_with_grn_and_eqn.sh
index 972331c77..e0709440f 100755
--- a/src/roff/groff/tests/html_works_with_grn_and_eqn.sh
+++ b/src/roff/groff/tests/html_works_with_grn_and_eqn.sh
@@ -20,6 +20,17 @@
 
 groff="${abs_top_builddir:-.}/test-groff"
 
+# Keep this list of programs in sync with GROFF_CHECK_GROHTML_PROGRAMS
+# in m4/groff.m4.
+for cmd in pnmcrop pnmcut pnmtopng pnmtops psselect
+do
+    if ! command -v $cmd >/dev/null
+    then
+        echo "cannot locate '$cmd' command; skipping test" >&2
+        exit 77 # skip
+    fi
+done
+
 # Commit c71b4ef4aa provoked an infinite loop in post-grohtml with these
 # preprocessors.
 
diff --git a/src/roff/groff/tests/smoke-test_html_device.sh b/src/roff/groff/tests/smoke-test_html_device.sh
index efdaa0449..877fc28fb 100755
--- a/src/roff/groff/tests/smoke-test_html_device.sh
+++ b/src/roff/groff/tests/smoke-test_html_device.sh
@@ -20,6 +20,17 @@
 
 groff="${abs_top_builddir:-.}/test-groff"
 
+# Keep this list of programs in sync with GROFF_CHECK_GROHTML_PROGRAMS
+# in m4/groff.m4.
+for cmd in pnmcrop pnmcut pnmtopng pnmtops psselect
+do
+    if ! command -v $cmd >/dev/null
+    then
+        echo "cannot locate '$cmd' command; skipping test" >&2
+        exit 77 # skip
+    fi
+done
+
 fail=
 
 wail () {