tests: vfmt test for all vlib/v files

vlib/v/fmt/fmt_keep_test.v

@@ -23,7 +23,9 @@ fn test_fmt() {
 	}
 	vroot := os.dir(vexe)
 	tmpfolder := os.temp_dir()
-	diff_cmd := util.find_working_diff_command() or { '' }
+	diff_cmd := util.find_working_diff_command() or {
+		''
+	}
 	mut fmt_bench := benchmark.new_benchmark()
 	keep_input_files := os.walk_ext('$vroot/vlib/v/fmt/tests', '_keep.vv')
 	expected_input_files := os.walk_ext('$vroot/vlib/v/fmt/tests', '_expected.vv')

vlib/v/fmt/fmt_vlib_test.v

@@ -0,0 +1,71 @@
+import os
+import term
+import benchmark
+import v.ast
+import v.fmt
+import v.parser
+import v.table
+import v.pref
+import v.util
+
+const (
+	error_missing_vexe = 1
+	error_failed_tests = 2
+)
+
+fn test_vlib_fmt() {
+	$if !freebsd {
+		return
+	}
+	fmt_message := "checking that all V source files are vfmt'ed"
+	eprintln(term.header(fmt_message, '-'))
+	vexe := os.getenv('VEXE')
+	if vexe.len == 0 || !os.exists(vexe) {
+		eprintln('VEXE must be set')
+		exit(error_missing_vexe)
+	}
+	vroot := os.dir(vexe)
+	tmpfolder := os.temp_dir()
+	diff_cmd := util.find_working_diff_command() or {
+		''
+	}
+	mut fmt_bench := benchmark.new_benchmark()
+	input_files := os.walk_ext('$vroot/vlib/v/', '.v')
+	fmt_bench.set_total_expected_steps(input_files.len)
+	for istep, ipath in input_files {
+		fmt_bench.cstep = istep
+		fmt_bench.step()
+		ifilename := os.file_name(ipath)
+		opath := ipath
+		expected_ocontent := os.read_file(opath) or {
+			fmt_bench.fail()
+			eprintln(fmt_bench.step_message_fail('cannot read from ${opath}'))
+			continue
+		}
+		table := table.new_table()
+		file_ast := parser.parse_file(ipath, table, .parse_comments, &pref.Preferences{}, &ast.Scope{
+			parent: 0
+		})
+		result_ocontent := fmt.fmt(file_ast, table, false)
+		if expected_ocontent != result_ocontent {
+			fmt_bench.fail()
+			eprintln(fmt_bench.step_message_fail('file ${ipath} after formatting, does not look as expected.'))
+			if diff_cmd == '' {
+				eprintln('>> sorry, but no working "diff" CLI command can be found')
+				continue
+			}
+			vfmt_result_file := os.join_path(tmpfolder, 'vfmt_run_over_${ifilename}')
+			os.write_file(vfmt_result_file, result_ocontent)
+			eprintln(util.color_compare_files(diff_cmd, opath, vfmt_result_file))
+			continue
+		}
+		fmt_bench.ok()
+		eprintln(fmt_bench.step_message_ok('${ipath}'))
+	}
+	fmt_bench.stop()
+	eprintln(term.h_divider('-'))
+	eprintln(fmt_bench.total_message(fmt_message))
+	if fmt_bench.nfail > 0 {
+		exit(error_failed_tests)
+	}
+}