feat(operators): add error return scenarios for custom operator null fallback (#342)

Signed-off-by: Simon Schrottner <simon.schrottner@dynatrace.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: aepfli

evaluator/flags/testkit-flags.json

@@ -446,6 +446,34 @@
           "small"
         ]
       }
+    },
+    "semver-invalid-version-flag": {
+      "state": "ENABLED",
+      "variants": { "match": "match", "no-match": "no-match", "fallback": "fallback" },
+      "defaultVariant": "fallback",
+      "targeting": {
+        "sem_ver": [{"var": "version"}, "=", "1.0.0"]
+      }
+    },
+    "semver-invalid-operator-flag": {
+      "state": "ENABLED",
+      "variants": { "match": "match", "no-match": "no-match", "fallback": "fallback" },
+      "defaultVariant": "fallback",
+      "targeting": {
+        "sem_ver": [{"var": "version"}, "===", "1.0.0"]
+      }
+    },
+    "fractional-null-bucket-key-flag": {
+      "state": "ENABLED",
+      "variants": { "one": "one", "two": "two", "fallback": "fallback" },
+      "defaultVariant": "fallback",
+      "targeting": {
+        "fractional": [
+          {"var": "missing_key"},
+          ["one", 50],
+          ["two", 50]
+        ]
+      }
     }
   },
   "$evaluators": {

evaluator/gherkin/fractional.feature

@@ -181,3 +181,10 @@ Feature: Evaluator fractional operator
     And a context containing a targeting key with value "some-targeting-key"
     When the flag was evaluated with details
     Then the resolved details value should be "ones"
+
+  @operator-errors
+  Scenario: fractional operator with missing bucket key falls back to default variant
+    Given an evaluator
+    And a String-flag with key "fractional-null-bucket-key-flag" and a fallback value "wrong"
+    When the flag was evaluated with details
+    Then the resolved details value should be "fallback"

evaluator/gherkin/semver.feature

@@ -31,3 +31,15 @@ Feature: Evaluator semantic version operator
       | 3.0.1   | minor |
       | 3.1.0   | major |
       | 4.0.0   | none  |
+
+  @operator-errors
+  Scenario Outline: sem_ver returns null for invalid input and falls back to default variant
+    Given an evaluator
+    And a String-flag with key "<key>" and a fallback value "wrong"
+    And a context containing a key "version", with type "String" and with value "<context_value>"
+    When the flag was evaluated with details
+    Then the resolved details value should be "fallback"
+    Examples:
+      | key                          | context_value |
+      | semver-invalid-version-flag  | not-a-version |
+      | semver-invalid-operator-flag | 1.0.0         |

flags/edge-case-flags.json

@@ -52,6 +52,46 @@
       },
       "defaultVariant": "false",
       "targeting": {}
+    },
+    "semver-invalid-version-flag": {
+      "state": "ENABLED",
+      "variants": {
+        "match": "match",
+        "no-match": "no-match",
+        "fallback": "fallback"
+      },
+      "defaultVariant": "fallback",
+      "targeting": {
+        "sem_ver": [{"var": "version"}, "=", "1.0.0"]
+      }
+    },
+    "semver-invalid-operator-flag": {
+      "state": "ENABLED",
+      "variants": {
+        "match": "match",
+        "no-match": "no-match",
+        "fallback": "fallback"
+      },
+      "defaultVariant": "fallback",
+      "targeting": {
+        "sem_ver": [{"var": "version"}, "===", "1.0.0"]
+      }
+    },
+    "fractional-null-bucket-key-flag": {
+      "state": "ENABLED",
+      "variants": {
+        "one": "one",
+        "two": "two",
+        "fallback": "fallback"
+      },
+      "defaultVariant": "fallback",
+      "targeting": {
+        "fractional": [
+          {"var": "missing_key"},
+          ["one", 50],
+          ["two", 50]
+        ]
+      }
     }
   }
 }

gherkin/targeting.feature

@@ -273,3 +273,20 @@ Feature: Targeting rules
       | missing-variant-targeting-flag    | 3     | GENERAL     |
       | non-string-variant-targeting-flag | 2     |             |
       | empty-targeting-flag              | 1     |             |
+
+  @operator-errors
+  Scenario Outline: Custom operator errors return null and fall back to default variant
+    Given a String-flag with key "<key>" and a default value "wrong"
+    And a context containing a key "version", with type "String" and with value "<context_value>"
+    When the flag was evaluated with details
+    Then the resolved details value should be "fallback"
+    Examples:
+      | key                          | context_value   |
+      | semver-invalid-version-flag  | not-a-version   |
+      | semver-invalid-operator-flag | 1.0.0           |
+
+  @operator-errors
+  Scenario: fractional operator with missing bucket key falls back to default variant
+    Given a String-flag with key "fractional-null-bucket-key-flag" and a default value "wrong"
+    When the flag was evaluated with details
+    Then the resolved details value should be "fallback"