chore: handle edge cases with RandomDecimalGenerator

pact-foundation · Sep 20, 2020 · 2a1cdf5 · 2a1cdf5
1 parent 6e0b293
commit 2a1cdf5
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Showing 2 changed files with 31 additions and 14 deletions.
diff --git a/core/model/src/main/kotlin/au/com/dius/pact/core/model/generators/Generator.kt b/core/model/src/main/kotlin/au/com/dius/pact/core/model/generators/Generator.kt
@@ -127,21 +127,28 @@ data class RandomDecimalGenerator(val digits: Int) : Generator {
   }
 
   override fun generate(context: Map<String, Any?>): Any {
-    val sampleDigits = RandomStringUtils.randomNumeric(digits + 1)
-    val pos = RandomUtils.nextInt(1, digits - 1)
-    val selectedDigits = if (sampleDigits.startsWith("00")) {
-      RandomUtils.nextInt(1, 9).toString() + sampleDigits.substring(1, digits)
-    } else if (pos != 1 && sampleDigits.startsWith('0')) {
-      sampleDigits.substring(1)
-    } else {
-      sampleDigits.substring(0, digits)
-    }
-    val generated = "${selectedDigits.substring(0, pos)}.${selectedDigits.substring(pos)}"
-    logger.trace {
-      "RandomDecimalGenerator: sampleDigits=[$sampleDigits], pos=$pos, selectedDigits=[$selectedDigits], " +
-        "generated=[$generated]"
+    return when {
+      digits < 1 -> throw UnsupportedOperationException("RandomDecimalGenerator digits must be > 0, got $digits")
+      digits == 1 -> BigDecimal(RandomUtils.nextInt(0, 9))
+      digits == 2 -> BigDecimal("${RandomUtils.nextInt(0, 9)}.${RandomUtils.nextInt(0, 9)}")
+      else -> {
+        val sampleDigits = RandomStringUtils.randomNumeric(digits + 1)
+        val pos = RandomUtils.nextInt(1, digits - 1)
+        val selectedDigits = if (sampleDigits.startsWith("00")) {
+          RandomUtils.nextInt(1, 9).toString() + sampleDigits.substring(1, digits)
+        } else if (pos != 1 && sampleDigits.startsWith('0')) {
+          sampleDigits.substring(1)
+        } else {
+          sampleDigits.substring(0, digits)
+        }
+        val generated = "${selectedDigits.substring(0, pos)}.${selectedDigits.substring(pos)}"
+        logger.trace {
+          "RandomDecimalGenerator: sampleDigits=[$sampleDigits], pos=$pos, selectedDigits=[$selectedDigits], " +
+            "generated=[$generated]"
+        }
+        BigDecimal(generated)
+      }
     }
-    return BigDecimal(generated)
   }
 
   companion object {

diff --git a/.../src/test/groovy/au/com/dius/pact/core/model/generators/RandomDecimalGeneratorSpec.groovy b/.../src/test/groovy/au/com/dius/pact/core/model/generators/RandomDecimalGeneratorSpec.groovy
@@ -20,4 +20,14 @@ class RandomDecimalGeneratorSpec extends Specification {
     where:
     _samples << (1..100).step(1)
   }
+
+  def 'handle edge case when digits == 1'() {
+    expect:
+    new RandomDecimalGenerator(1).generate([:]).toString() ==~ /^\d/
+  }
+
+  def 'handle edge case when digits == 2'() {
+    expect:
+    new RandomDecimalGenerator(2).generate([:]).toString() ==~ /^\d\.\d/
+  }
 }