t: add test for querying cores-per-node info

Problem: flux-accounting has no tests for estimating the cores-per-node
count by fetching resource.R from the KVS and then querying it from the
plugin.

Add some basic tests.

t/Makefile.am

@@ -36,6 +36,7 @@ TESTSCRIPTS = \
 	t1033-mf-priority-update-job.t \
 	t1034-mf-priority-config.t \
 	t1035-flux-account-scrub-old-jobs.t \
+	t1036-mf-priority-resource-counting.t \
 	t5000-valgrind.t \
 	python/t1000-example.py \
 	python/t1001_db.py \

t/t1036-mf-priority-resource-counting.t

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+test_description='test calculating and storing system core information in priority plugin'
+
+. `dirname $0`/sharness.sh
+
+mkdir -p conf.d
+
+MULTI_FACTOR_PRIORITY=${FLUX_BUILD_DIR}/src/plugins/.libs/mf_priority.so
+
+export TEST_UNDER_FLUX_SCHED_SIMPLE_MODE="limited=1"
+test_under_flux 4 job -o,--config-path=$(pwd)/conf.d
+
+flux setattr log-stderr-level 1
+
+test_expect_success 'load multi-factor priority plugin' '
+	flux jobtap load -r .priority-default ${MULTI_FACTOR_PRIORITY}
+'
+
+test_expect_success 'check that mf_priority plugin is loaded' '
+	flux jobtap list | grep mf_priority
+'
+
+test_expect_success 'check that cores-per-node count is correct' '
+	flux jobtap query mf_priority.so > query.json &&
+	test_debug "jq -S . <query.json" &&
+	flux resource R --include=0 | flux R decode --count=core > ncores_per_node.test &&
+	jq -e ".ncores_per_node == $(cat ncores_per_node.test)" <query.json
+'
+
+test_done