Add isEmpty method to EntryValue

kotpass/src/main/kotlin/app/keemobile/kotpass/models/EntryValue.kt

@@ -11,12 +11,19 @@ sealed class EntryValue {
      */
     abstract val content: String
 
+    /**
+     * Checks whether [content] is empty without exposing [EncryptedValue].
+     */
+    abstract fun isEmpty(): Boolean
+
     /**
      * Should be used for non-sensitive values.
      */
     data class Plain(
         override val content: String
-    ) : EntryValue()
+    ) : EntryValue() {
+        override fun isEmpty() = content.isEmpty()
+    }
 
     /**
      * Should be used for secrets.
@@ -25,6 +32,8 @@ sealed class EntryValue {
         private val value: EncryptedValue
     ) : EntryValue() {
         override val content: String get() = value.text
+
+        override fun isEmpty() = value.byteLength == 0
     }
 
     /**

kotpass/src/test/kotlin/app/keemobile/kotpass/models/EntryValueSpec.kt

@@ -0,0 +1,23 @@
+package app.keemobile.kotpass.models
+
+import app.keemobile.kotpass.cryptography.EncryptedValue
+import io.kotest.core.spec.style.DescribeSpec
+import io.kotest.matchers.shouldBe
+
+class EntryValueSpec : DescribeSpec({
+
+    describe("EntryValue") {
+        it("isEmpty check properly evaluates empty string") {
+            val emptyPlain = EntryValue.Plain("")
+            val emptyEncrypted = EntryValue.Encrypted(EncryptedValue.fromString(""))
+            val somePlain = EntryValue.Encrypted(EncryptedValue.fromString("123"))
+            val someEncrypted = EntryValue.Encrypted(EncryptedValue.fromString("123"))
+
+            emptyPlain.isEmpty() shouldBe true
+            emptyEncrypted.isEmpty() shouldBe true
+
+            somePlain.isEmpty() shouldBe false
+            someEncrypted.isEmpty() shouldBe false
+        }
+    }
+})