adds more meaningful messages to assertion errors

lib/sympto/index.js

@@ -100,20 +100,20 @@ export default function getSymptoThermalStatus(cycleInfo) {
 
 function throwIfArgsAreNotInRequiredFormat(cycles) {
   cycles.forEach(cycle => {
-    assert.ok(Array.isArray(cycle))
-    assert.ok(cycle.length > 0) //what about 2 cycles of 1 day each?!
-    assert.ok(cycle[0].bleeding !== null)
-    assert.equal(typeof cycle[0].bleeding, 'object', "First cycle day must contain bleeding value")
-    assert.equal(typeof cycle[0].bleeding.value, 'number')
+    assert.ok(Array.isArray(cycle), "Cycles must be arrays.")
+    assert.ok(cycle.length > 0, "Cycle must not be empty.") //what about 2 cycles of 1 day each?!
+    assert.ok(cycle[0].bleeding !== null, "First cycle day should have bleeding.")
+    assert.equal(typeof cycle[0].bleeding, 'object', "First cycle day must contain bleeding value.")
+    assert.equal(typeof cycle[0].bleeding.value, 'number', "First cycle day bleeding value is a number.")
     cycle.forEach(day => {
-      assert.equal(typeof day.date, 'string')
-      assert.doesNotThrow(() => LocalDate.parse(day.date))
-      if (day.temperature) assert.equal(typeof day.temperature.value, 'number')
-      if (day.mucus) assert.equal(typeof day.mucus.value, 'number')
-      if (day.mucus) assert.ok(day.mucus.value >= 0)
-      if (day.mucus) assert.ok(day.mucus.value < 5)
-      if (day.cervix) assert.equal(typeof day.cervix.isClosed, 'boolean')
-      if (day.cervix) assert.equal(typeof day.cervix.isHard, 'boolean')
+      assert.equal(typeof day.date, 'string', "Date is given as a string.")
+      assert.doesNotThrow(() => LocalDate.parse(day.date), "Date is given in right string format.")
+      if (day.temperature) assert.equal(typeof day.temperature.value, 'number', "Temperature value is a number.")
+      if (day.mucus) assert.equal(typeof day.mucus.value, 'number', "Mucus value is a number.")
+      if (day.mucus) assert.ok(day.mucus.value >= 0, "Mucus value is greater or equal to 0.")
+      if (day.mucus) assert.ok(day.mucus.value < 5, "Mucus value below 5.")
+      if (day.cervix) assert.equal(typeof day.cervix.isClosed, 'boolean', "Cervic.isClosed is a boolean.")
+      if (day.cervix) assert.equal(typeof day.cervix.isHard, 'boolean', "Cervic.isHard is a boolean.")
     })
   })
 }