diff --git a/conf_test.v b/conf_test.v
deleted file mode 100644
index 72e7703..0000000
--- a/conf_test.v
+++ /dev/null
@@ -1,43 +0,0 @@
-module conf
-
-struct SimpleConf {
-	some_int    int
-	some_string string
-}
-
-struct SimpleConfDefaults {
-	some_int    int    = 3
-	some_string string = 'hi'
-}
-
-fn test_simple() {
-	conf := load<SimpleConf>(default_path: 'test/test_simple.toml')!
-	assert conf == SimpleConf{
-		some_int: 2
-		some_string: 'hi'
-	}
-}
-
-fn test_zeroed() {
-	conf := load<SimpleConf>(default_path: 'test/test_zeroed.toml')!
-	assert conf == SimpleConf{
-		some_int: 0
-		some_string: ''
-	}
-}
-
-fn test_zeroed_defaults() {
-	conf := load<SimpleConfDefaults>(default_path: 'test/test_zeroed.toml')!
-	assert conf == SimpleConfDefaults{
-		some_int: 0
-		some_string: ''
-	}
-}
-
-fn test_defaults() {
-	conf := load<SimpleConfDefaults>(default_path: 'test/test_single_value.toml')!
-	assert conf == SimpleConfDefaults{
-		some_int: 3
-		some_string: 'hi'
-	}
-}
diff --git a/int_test.v b/int_test.v
new file mode 100644
index 0000000..e248319
--- /dev/null
+++ b/int_test.v
@@ -0,0 +1,183 @@
+module conf
+
+struct SingleConf {
+	some_int int
+}
+
+struct SingleConfDefault {
+	some_int int = 2
+}
+
+fn test_int_present_no_default() {
+	mut conf := load<SingleConf>(default_path: 'test/int.toml')!
+	assert conf == SingleConf{
+		some_int: 1
+	}
+
+	conf = load<SingleConf>(default_path: 'test/int_zero.toml')!
+	assert conf == SingleConf{
+		some_int: 0
+	}
+}
+
+fn test_int_present_no_default_env() {
+	mut conf := load<SingleConf>(
+		default_path: 'test/int.toml'
+		env: {
+			'SOME_INT': '3'
+		}
+	)!
+	assert conf == SingleConf{
+		some_int: 3
+	}
+
+	conf = load<SingleConf>(
+		default_path: 'test/int.toml'
+		env: {
+			'SOME_INT': ''
+		}
+	)!
+	assert conf == SingleConf{
+		some_int: 0
+	}
+
+	conf = load<SingleConf>(
+		default_path: 'test/int.toml'
+		env: {
+			'TEST_SOME_INT': '3'
+		}
+		prefix: 'TEST_'
+	)!
+	assert conf == SingleConf{
+		some_int: 3
+	}
+}
+
+fn test_int_absent_no_default() {
+	conf := load<SingleConf>(default_path: 'test/empty.toml') or { return }
+	assert false
+}
+
+fn test_int_absent_no_default_env() {
+	mut conf := load<SingleConf>(
+		default_path: 'test/int.toml'
+		env: {
+			'SOME_INT': '3'
+		}
+	)!
+	assert conf == SingleConf{
+		some_int: 3
+	}
+
+	conf = load<SingleConf>(
+		default_path: 'test/int.toml'
+		env: {
+			'SOME_INT': ''
+		}
+	)!
+	assert conf == SingleConf{
+		some_int: 0
+	}
+
+	conf = load<SingleConf>(
+		default_path: 'test/int.toml'
+		env: {
+			'TEST_SOME_INT': '3'
+		}
+		prefix: 'TEST_'
+	)!
+	assert conf == SingleConf{
+		some_int: 3
+	}
+}
+
+fn test_int_present_default() {
+	conf := load<SingleConfDefault>(default_path: 'test/int.toml')!
+	assert conf == SingleConfDefault{
+		some_int: 1
+	}
+}
+
+fn test_int_present_default_env() {
+	mut conf := load<SingleConfDefault>(
+		default_path: 'test/int.toml'
+		env: {
+			'SOME_INT': '3'
+		}
+	)!
+	assert conf == SingleConfDefault{
+		some_int: 3
+	}
+
+	conf = load<SingleConfDefault>(
+		default_path: 'test/int.toml'
+		env: {
+			'SOME_INT': ''
+		}
+	)!
+	assert conf == SingleConfDefault{
+		some_int: 0
+	}
+
+	conf = load<SingleConfDefault>(
+		default_path: 'test/int.toml'
+		env: {
+			'TEST_SOME_INT': '3'
+		}
+		prefix: 'TEST_'
+	)!
+	assert conf == SingleConfDefault{
+		some_int: 3
+	}
+}
+
+fn test_int_absent_default() {
+	conf := load<SingleConfDefault>(default_path: 'test/empty.toml')!
+	assert conf == SingleConfDefault{
+		some_int: 2
+	}
+}
+
+fn test_int_absent_default_env() {
+	mut conf := load<SingleConfDefault>(
+		default_path: 'test/empty.toml'
+		env: {
+			'SOME_INT': '3'
+		}
+	)!
+	assert conf == SingleConfDefault{
+		some_int: 3
+	}
+
+	conf = load<SingleConfDefault>(
+		default_path: 'test/empty.toml'
+		env: {
+			'SOME_INT': ''
+		}
+	)!
+	assert conf == SingleConfDefault{
+		some_int: 0
+	}
+
+	conf = load<SingleConfDefault>(
+		default_path: 'test/empty.toml'
+		env: {
+			'TEST_SOME_INT': '3'
+		}
+		prefix: 'TEST_'
+	)!
+	assert conf == SingleConfDefault{
+		some_int: 3
+	}
+}
+
+struct SingleConfDefaultEmpty {
+	some_int int [empty_default]
+}
+
+fn test_int_absent_default_empty() {
+	conf := load<SingleConfDefaultEmpty>(default_path: 'test/empty.toml')!
+	assert conf == SingleConfDefaultEmpty{
+		some_int: 0
+	}
+}
diff --git a/string_test.v b/string_test.v
index 9dfc191..9c7a6a9 100644
--- a/string_test.v
+++ b/string_test.v
@@ -9,13 +9,13 @@ struct SingleConfDefault {
 }
 
 fn test_string_present_no_default() {
-	conf := load<SingleConf>(default_path: 'test/string.toml')!
+	mut conf := load<SingleConf>(default_path: 'test/string.toml')!
 	assert conf == SingleConf{
 		some_string: 'hi'
 	}
 
-	conf2 := load<SingleConf>(default_path: 'test/string_empty.toml')!
-	assert conf2 == SingleConf{
+	conf = load<SingleConf>(default_path: 'test/string_empty.toml')!
+	assert conf == SingleConf{
 		some_string: ''
 	}
 }
diff --git a/test/int.toml b/test/int.toml
index 263b0ce..b8326e0 100644
--- a/test/int.toml
+++ b/test/int.toml
@@ -1 +1 @@
-some_int = "hi"
+some_int = 1
diff --git a/test/int_zero.toml b/test/int_zero.toml
new file mode 100644
index 0000000..4dd4d46
--- /dev/null
+++ b/test/int_zero.toml
@@ -0,0 +1 @@
+some_int = 0
diff --git a/test/test_simple.toml b/test/test_simple.toml
deleted file mode 100644
index 489eea3..0000000
--- a/test/test_simple.toml
+++ /dev/null
@@ -1,2 +0,0 @@
-some_int = 2
-some_string = "hi"
diff --git a/test/test_single_value.toml b/test/test_single_value.toml
deleted file mode 100644
index 85c27d0..0000000
--- a/test/test_single_value.toml
+++ /dev/null
@@ -1 +0,0 @@
-some_string = "hi"
diff --git a/test/test_zeroed.toml b/test/test_zeroed.toml
deleted file mode 100644
index ce4dd51..0000000
--- a/test/test_zeroed.toml
+++ /dev/null
@@ -1,2 +0,0 @@
-some_int = 0
-some_string = ""