diff --git a/pkg/expressions/funcfile/example.funcfile b/pkg/expressions/funcfile/example.funcfile
new file mode 100644
index 0000000..179c932
--- /dev/null
+++ b/pkg/expressions/funcfile/example.funcfile
@@ -0,0 +1,2 @@
+# test func
+double {sumi {0} {0}}
\ No newline at end of file
diff --git a/pkg/expressions/funcfile/loader_test.go b/pkg/expressions/funcfile/loader_test.go
new file mode 100644
index 0000000..463b590
--- /dev/null
+++ b/pkg/expressions/funcfile/loader_test.go
@@ -0,0 +1,55 @@
+package funcfile
+
+import (
+	"rare/pkg/expressions/stdlib"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLoadDefinitions(t *testing.T) {
+	data := `# a comment
+	double {sumi {0} {0}}
+	
+	# Another comment
+	quad this equals: \
+	  {multi \
+		{0} \
+		{0} \
+		#Mixed comment
+		{0} {0}}
+	`
+	kb := stdlib.NewStdKeyBuilder()
+	funcs, err := LoadDefinitions(kb, strings.NewReader(data))
+	assert.NoError(t, err)
+	assert.Len(t, funcs, 2)
+	assert.Contains(t, funcs, "quad")
+	assert.Contains(t, funcs, "double")
+
+	val, err := kb.Compile("{quad 5}")
+	assert.Nil(t, err)
+	assert.Equal(t, "this equals: 625", val.BuildKey(nil))
+}
+
+func TestLoadDefinitionsErrs(t *testing.T) {
+	data := `# a comment
+	unterm unterm {
+	nofunc
+
+	`
+	kb := stdlib.NewStdKeyBuilder()
+	funcs, err := LoadDefinitions(kb, strings.NewReader(data))
+	assert.NotNil(t, err)
+	assert.Len(t, funcs, 0)
+}
+
+func TestLoadFile(t *testing.T) {
+	kb := stdlib.NewStdKeyBuilder()
+	funcs, err := LoadDefinitionsFile(kb, "example.funcfile")
+	assert.NoError(t, err)
+	assert.Len(t, funcs, 1)
+
+	_, err = LoadDefinitionsFile(kb, "notfile.funcfile")
+	assert.Error(t, err)
+}
diff --git a/pkg/expressions/funcfile/stage_test.go b/pkg/expressions/funcfile/stage_test.go
index b5cf8c6..09b54a3 100644
--- a/pkg/expressions/funcfile/stage_test.go
+++ b/pkg/expressions/funcfile/stage_test.go
@@ -26,6 +26,17 @@ func TestCustomFunc(t *testing.T) {
 	assert.Equal(t, val, "kd: 250")
 }
 
+func TestCustomEdgeCases(t *testing.T) {
+	k := stdlib.NewStdKeyBuilder()
+	_, err := createAndAddFunc(k, "err", "{unclosed func")
+	assert.Error(t, err)
+
+	_, err = createAndAddFunc(k, "doublesrc", "{test} {sumi {0} {0}} missing: {1}")
+	assert.NoError(t, err)
+	kb, _ := k.Compile("{doublesrc 5}")
+	assert.Equal(t, "testval 10 missing: ", kb.BuildKey(&testContext))
+}
+
 // BenchmarkCustomFunc-4   	 4767489	       244.2 ns/op	      16 B/op	       2 allocs/op
 // BenchmarkCustomFunc-4   	 7563214	       160.4 ns/op	       3 B/op	       1 allocs/op
 func BenchmarkCustomFunc(b *testing.B) {