diff --git a/config/config_test.go b/config/config_test.go
new file mode 100644
index 0000000..2712936
--- /dev/null
+++ b/config/config_test.go
@@ -0,0 +1,89 @@
+package config
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"reflect"
+	"testing"
+)
+
+func newTestConfiguration() *configuration {
+	return &configuration{
+		Server: server{
+			Address: "127.0.0.1",
+			Port:    3000,
+		},
+		Nomad: nomad{
+			Address: "127.0.0.2",
+			Token:   "SECRET",
+			TLS:     false,
+		},
+		Logger: logger{
+			Level: "INFO",
+		},
+	}
+}
+
+func (c *configuration) getReflectValue() reflect.Value {
+	return reflect.ValueOf(c).Elem()
+}
+
+func TestIntEnvironmentVariableOverwritesConfig(t *testing.T) {
+	config := newTestConfiguration()
+	_ = os.Setenv("POSEIDON_TEST_SERVER_PORT", "4000")
+	readFromEnvironment("POSEIDON_TEST", config.getReflectValue())
+	_ = os.Unsetenv("POSEIDON_TEST_SERVER_PORT")
+	assert.Equal(t, 4000, config.Server.Port)
+}
+
+func TestStringEnvironmentVariableOverwritesConfig(t *testing.T) {
+	config := newTestConfiguration()
+	_ = os.Setenv("POSEIDON_TEST_NOMAD_TOKEN", "ACCESS")
+	readFromEnvironment("POSEIDON_TEST", config.getReflectValue())
+	_ = os.Unsetenv("POSEIDON_TEST_NOMAD_TOKEN")
+	assert.Equal(t, "ACCESS", config.Nomad.Token)
+}
+
+func TestBoolEnvironmentVariableOverwritesConfig(t *testing.T) {
+	config := newTestConfiguration()
+	_ = os.Setenv("POSEIDON_TEST_NOMAD_TLS", "true")
+	readFromEnvironment("POSEIDON_TEST", config.getReflectValue())
+	_ = os.Unsetenv("POSEIDON_TEST_NOMAD_TLS")
+	assert.Equal(t, true, config.Nomad.TLS)
+}
+
+func TestUnsetEnvironmentVariableDoesNotChangeConfig(t *testing.T) {
+	config := newTestConfiguration()
+	readFromEnvironment("POSEIDON_TEST", config.getReflectValue())
+	assert.Equal(t, "INFO", config.Logger.Level)
+}
+
+func TestIntYamlVariableOverwritesConfig(t *testing.T) {
+	config := newTestConfiguration()
+	config.mergeYaml([]byte("server:\n  port: 5000\n"))
+	assert.Equal(t, 5000, config.Server.Port)
+}
+
+func TestStringYamlVariableOverwritesConfig(t *testing.T) {
+	config := newTestConfiguration()
+	config.mergeYaml([]byte("logger:\n  level: DEBUG\n"))
+	assert.Equal(t, "DEBUG", config.Logger.Level)
+}
+
+func TestBoolYamlVariableOverwritesConfig(t *testing.T) {
+	config := newTestConfiguration()
+	config.mergeYaml([]byte("nomad:\n  tls: true\n"))
+	assert.Equal(t, true, config.Nomad.TLS)
+}
+
+func TestMissingYamlVariableDoesNotChangeConfig(t *testing.T) {
+	config := newTestConfiguration()
+	config.mergeYaml([]byte(""))
+	assert.Equal(t, "127.0.0.2", config.Nomad.Address)
+}
+
+func TestUnsetYamlVariableDoesNotChangeConfig(t *testing.T) {
+	config := newTestConfiguration()
+	config.mergeYaml([]byte("nomad:\n  address:\n"))
+	assert.Equal(t, "127.0.0.2", config.Nomad.Address)
+}