combine repetitive code into convenience function

unittest/force-styles/test_main.cpp

@@ -16,16 +16,19 @@
 #include "test_config.h"
 #include "test_config_reader.h"
 #include "utils.h"
+#include "yaml_writer.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
 #include <cstdlib>
 #include <cstring>
+#include <ctime>
 #include <iostream>
 #include <mpi.h>
 #include <vector>
 
 using LAMMPS_NS::utils::split_words;
+using LAMMPS_NS::utils::trim;
 
 // common read_yaml_file function
 bool read_yaml_file(const char *infile, TestConfig &config)
@@ -37,6 +40,55 @@ bool read_yaml_file(const char *infile, TestConfig &config)
     return true;
 }
 
+// write out common header items for yaml files
+void write_yaml_header(YamlWriter *writer,
+                       TestConfig *cfg,
+                       const char *version)
+{
+    // lammps_version
+    writer->emit("lammps_version", version);
+
+    // date_generated
+    std::time_t now = time(NULL);
+    std::string block = trim(ctime(&now));
+    writer->emit("date_generated", block);
+
+    // epsilon
+    writer->emit("epsilon", cfg->epsilon);
+
+    // skip tests
+    block.clear();
+    for (auto &skip : cfg->skip_tests) {
+        if (block.empty()) block = skip;
+        else block += " " + skip;
+    }
+    writer->emit("skip_tests", block);
+
+    // prerequisites
+    block.clear();
+    for (auto &prerequisite : cfg->prerequisites) {
+        block += prerequisite.first + " " + prerequisite.second + "\n";
+    }
+    writer->emit_block("prerequisites", block);
+
+    // pre_commands
+    block.clear();
+    for (auto &command : cfg->pre_commands) {
+        block += command + "\n";
+    }
+    writer->emit_block("pre_commands", block);
+
+    // post_commands
+    block.clear();
+    for (auto &command : cfg->post_commands) {
+        block += command + "\n";
+    }
+    writer->emit_block("post_commands", block);
+
+    // input_file
+    writer->emit("input_file", cfg->input_file);
+}
+
 // need to be defined in unit test body
 extern void generate_yaml_file(const char *, const TestConfig &);