diff --git a/include/spdlog/cfg/argv.h b/include/spdlog/cfg/argv.h
index 46624439..83dd3687 100644
--- a/include/spdlog/cfg/argv.h
+++ b/include/spdlog/cfg/argv.h
@@ -22,7 +22,7 @@ namespace spdlog {
 namespace cfg {
 namespace argv {
 // search for SPDLOG_LEVEL= in the args and use it to init the levels
-void load_levels(int args, char *argv[])
+void load_levels(int args, const char *argv[])
 {
     const std::string spdlog_level_prefix = "SPDLOG_LEVEL=";
     for (int i = 1; i < args; i++)
diff --git a/include/spdlog/cfg/log_levels.h b/include/spdlog/cfg/log_levels.h
index 0fce95e9..867fe96b 100644
--- a/include/spdlog/cfg/log_levels.h
+++ b/include/spdlog/cfg/log_levels.h
@@ -11,8 +11,7 @@ namespace spdlog {
 namespace cfg {
 class log_levels
 {
-    using levels_map = std::unordered_map<std::string, spdlog::level::level_enum>;
-    levels_map levels_;
+    std::unordered_map<std::string, spdlog::level::level_enum> levels_;
     spdlog::level::level_enum default_level_ = level::info;
 
 public:
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 3184e9b6..f57fe23e 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -23,7 +23,8 @@ set(SPDLOG_UTESTS_SOURCES
     test_fmt_helper.cpp
   	test_stdout_api.cpp
 	test_backtrace.cpp
-	test_create_dir.cpp)
+	test_create_dir.cpp
+	test_cfg.cpp)
 
 if(NOT SPDLOG_NO_EXCEPTIONS)
 	list(APPEND SPDLOG_UTESTS_SOURCES test_errors.cpp)
diff --git a/tests/includes.h b/tests/includes.h
index 2fd30370..98734b18 100644
--- a/tests/includes.h
+++ b/tests/includes.h
@@ -11,6 +11,7 @@
 #include <sstream>
 #include <string>
 #include <iomanip>
+#include <stdlib.h>
 
 #define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_DEBUG
 
diff --git a/tests/meson.build b/tests/meson.build
index 24feb0a6..d59e702c 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -14,7 +14,8 @@ test_sources = files([
     'test_fmt_helper.cpp',
     'test_stdout_api.cpp',
     'test_backtrace.cpp',
-    'test_create_dir.cpp'
+    'test_create_dir.cpp',
+    'test_cfg.cpp',
 ])
 
 if  not get_option('no_exceptions')
diff --git a/tests/test_cfg.cpp b/tests/test_cfg.cpp
index 2bef6ef7..2d7b9419 100644
--- a/tests/test_cfg.cpp
+++ b/tests/test_cfg.cpp
@@ -2,9 +2,56 @@
 #include "test_sink.h"
 
 #include <spdlog/cfg/env.h>
+#include <spdlog/cfg/argv.h>
 
-TEST_CASE("env", "[cfg]")
+TEST_CASE("env", "[loaders]")
 {
-    spdlog::logger l{"l1"};
+    auto l1 = spdlog::create<spdlog::sinks::test_sink_st >("l1");
+    setenv("SPDLOG_LEVEL", "l1=warn", 1);
+    spdlog::cfg::env::load_levels();
+    REQUIRE(l1->level() == spdlog::level::warn);
+    REQUIRE(spdlog::default_logger()->level() == spdlog::level::info);
+    spdlog::drop(l1->name());
 }
 
+TEST_CASE("argv1", "[loaders]")
+{
+    const char* argv[] = {"ignore", "SPDLOG_LEVEL=l1=warn"};
+    spdlog::cfg::argv::load_levels(2, argv);
+    auto l1 = spdlog::create<spdlog::sinks::test_sink_st>("l1");
+    REQUIRE(l1->level() == spdlog::level::warn);
+    REQUIRE(spdlog::default_logger()->level() == spdlog::level::info);
+    spdlog::drop(l1->name());
+}
+
+TEST_CASE("argv2", "[loaders]")
+{
+    const char* argv[] = {"ignore", "SPDLOG_LEVEL=l1=warn,trace"};
+    spdlog::cfg::argv::load_levels(2, argv);
+    auto l1 = spdlog::create<spdlog::sinks::test_sink_st>("l1");
+    REQUIRE(l1->level() == spdlog::level::warn);
+    REQUIRE(spdlog::default_logger()->level() == spdlog::level::trace);
+    spdlog::drop(l1->name());
+}
+
+TEST_CASE("argv3", "[loaders]")
+{
+    const char* argv[] = {"ignore", "SPDLOG_LEVEL="};
+    spdlog::cfg::argv::load_levels(2, argv);
+    auto l1 = spdlog::create<spdlog::sinks::test_sink_st>("l1");
+    REQUIRE(l1->level() == spdlog::level::info);
+    REQUIRE(spdlog::default_logger()->level() == spdlog::level::info);
+    spdlog::drop(l1->name());
+}
+
+TEST_CASE("argv4", "[loaders]")
+{
+    const char* argv[] = {"ignore", "SPDLOG_LEVEL=junk"};
+    spdlog::cfg::argv::load_levels(2, argv);
+    auto l1 = spdlog::create<spdlog::sinks::test_sink_st>("l1");
+    REQUIRE(l1->level() == spdlog::level::info);
+    spdlog::drop(l1->name());
+}
+
+
+