json: Add run_tests (#14609)

Adds run_tests.sh for the json project.

run_tests.sh is used as part of Chronos with cached builds:

https://github.com/google/oss-fuzz/tree/master/infra/chronos#chronos-feature--running-tests-of-a-project

---------

Signed-off-by: Arthur Chan <[email protected]>

Author: arthurscchan

projects/json/Dockerfile

@@ -19,4 +19,4 @@ RUN apt-get update && apt-get install -y binutils make
 
 RUN git clone --depth 1 -b develop https://github.com/nlohmann/json.git
 WORKDIR json/
-COPY build.sh *.options parse_afl_fuzzer.dict $SRC/
+COPY run_tests.sh build.sh *.options parse_afl_fuzzer.dict $SRC/

projects/json/build.sh

@@ -24,3 +24,13 @@ for F in $FUZZER_FILES; do
     cp $SRC/fuzzer-parse.options $OUT/$FUZZER.options
 done
 cp $SRC/parse_afl_fuzzer.dict $OUT/
+
+# Build unit tests
+mkdir build-tests
+pushd build-tests
+cmake ..
+make -C tests
+popd
+
+# Pre-download test data
+ctest --test-dir build-tests -R download_test_data

projects/json/run_tests.sh

@@ -0,0 +1,21 @@
+#!/bin/bash -eu
+#
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+################################################################################
+
+# Skip download of test data
+# Temporarily skip test-class_parser_cpp11 which throws exception
+ctest --test-dir build-tests -E "download_test_data|test-class_parser_cpp11"