Add test for findDirection function

Add a new test file, direction_test.go, to test the findDirection function with various input cases. This change helps ensure the reliability and expected functionality of the findDirection function.

direction_test.go

@@ -0,0 +1,37 @@
+// SPDX-FileCopyrightText: 2023 Winni Neessen <wn@neessen.dev>
+//
+// SPDX-License-Identifier: MIT
+
+package meteologix
+
+import (
+	"testing"
+)
+
+func TestFindDirection(t *testing.T) {
+	// Prepare test cases
+	tt := []struct {
+		v  float64
+		dm map[float64]string
+		er string
+	}{
+		{15, WindDirAbbrMap, "NbE"},
+		{47, WindDirAbbrMap, "NE"},
+		{200, WindDirAbbrMap, "SSW"},
+		{330, WindDirAbbrMap, "NWbN"},
+		{15, WindDirFullMap, "North by East"},
+		{47, WindDirFullMap, "Northeast"},
+		{200, WindDirFullMap, "South-Southwest"},
+		{330, WindDirFullMap, "Northwest by North"},
+	}
+
+	// Run tests
+	for _, tc := range tt {
+		t.Run("", func(t *testing.T) {
+			r := findDirection(tc.v, tc.dm)
+			if tc.er != r {
+				t.Errorf("findDirection failed, expected: %s, got: %s", tc.er, r)
+			}
+		})
+	}
+}