feat: calculate default values for LoRa channel_num and frequency (#664)

app/src/androidTest/java/com/geeksville/mesh/ChannelTest.kt

@@ -1,6 +1,7 @@
 package com.geeksville.mesh
 
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.geeksville.mesh.model.Channel
 import com.geeksville.mesh.model.ChannelSet
 import org.junit.Assert
 import org.junit.Test
@@ -15,4 +16,18 @@ class ChannelTest {
         Assert.assertTrue(ch.getChannelUrl().toString().startsWith(ChannelSet.prefix))
         Assert.assertEquals(ChannelSet(ch.getChannelUrl()), ch)
     }
-}
+
+    @Test
+    fun channelNumGood() {
+        val ch = Channel.default
+
+        Assert.assertEquals(20, ch.channelNum)
+    }
+
+    @Test
+    fun radioFreqGood() {
+        val ch = Channel.default
+
+        Assert.assertEquals(906.875f, ch.radioFreq)
+    }
+}