[haskell-http-client] add cli option customTestInstanceModule (#2406)

setting `customTestInstanceModule` will import typeclasses from the
specified module into tests/Instances.hs, to provide typeclass
instances for types not known by the generator

this property set using `--additional-properties`

example:
```
--additional-properties=customTestInstanceModule=CustomInstances
```

docs/generators/haskell-http-client.md

@@ -29,4 +29,5 @@ sidebar_label: haskell-http-client
 |useKatip|Sets the default value for the UseKatip cabal flag. If true, the katip package provides logging instead of monad-logger| |true|
 |dateTimeFormat|format string used to parse/render a datetime| |null|
 |dateFormat|format string used to parse/render a date| |%Y-%m-%d|
+|customTestInstanceModule|test module used to provide typeclass instances for types not known by the generator| |null|
 |hideGenerationTimestamp|Hides the generation timestamp when files are generated.| |true|

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellHttpClientCodegen.java

@@ -63,6 +63,7 @@ public class HaskellHttpClientCodegen extends DefaultCodegen implements CodegenC
     public static final String PROP_CABAL_VERSION = "cabalVersion";
     public static final String PROP_CONFIG_TYPE = "configType";
     public static final String PROP_DATETIME_FORMAT = "dateTimeFormat";
+    public static final String PROP_CUSTOM_TEST_INSTANCE_MODULE = "customTestInstanceModule";
     public static final String PROP_DATE_FORMAT = "dateFormat";
     public static final String PROP_GENERATE_ENUMS = "generateEnums";
     public static final String PROP_GENERATE_FORM_URLENCODED_INSTANCES = "generateFormUrlEncodedInstances";
@@ -270,6 +271,8 @@ public HaskellHttpClientCodegen() {
         cliOptions.add(CliOption.newString(PROP_DATETIME_FORMAT, "format string used to parse/render a datetime"));
         cliOptions.add(CliOption.newString(PROP_DATE_FORMAT, "format string used to parse/render a date").defaultValue(defaultDateFormat));
 
+        cliOptions.add(CliOption.newString(PROP_CUSTOM_TEST_INSTANCE_MODULE, "test module used to provide typeclass instances for types not known by the generator"));
+
         cliOptions.add(CliOption.newBoolean(CodegenConstants.HIDE_GENERATION_TIMESTAMP, CodegenConstants.HIDE_GENERATION_TIMESTAMP_DESC).defaultValue(Boolean.TRUE.toString()));
 
     }
@@ -320,9 +323,7 @@ public void setDateTimeFormat(String value) {
         setStringProp(PROP_DATETIME_FORMAT, value);
     }
 
-    public void setDateFormat(String value) {
-        setStringProp(PROP_DATE_FORMAT, value);
-    }
+    public void setDateFormat(String value) { setStringProp(PROP_DATE_FORMAT, value); }
 
     public void setCabalPackage(String value) {
         setStringProp(PROP_CABAL_PACKAGE, value);
@@ -353,6 +354,8 @@ public void setUseKatip(Boolean value) {
         this.useKatip = value;
     }
 
+    public void setCustomTestInstanceModule(String value) { setStringProp(PROP_CUSTOM_TEST_INSTANCE_MODULE, value); }
+
     private void setStringProp(String key, String value) {
         if (StringUtils.isBlank(value)) {
             additionalProperties.remove(key);
@@ -467,6 +470,9 @@ public void processOpts() {
         if (additionalProperties.containsKey(PROP_CONFIG_TYPE)) {
             setConfigType(additionalProperties.get(PROP_CONFIG_TYPE).toString());
         }
+        if (additionalProperties.containsKey(PROP_CUSTOM_TEST_INSTANCE_MODULE)) {
+            setCustomTestInstanceModule(additionalProperties.get(PROP_CUSTOM_TEST_INSTANCE_MODULE).toString());
+        }
     }
 
     @Override

modules/openapi-generator/src/main/resources/haskell-http-client/README.mustache

@@ -62,6 +62,7 @@ These options allow some customization of the code generation process.
 | baseModule                      | Set the base module namespace                                                                                                 |          | {{{baseModule}}}                      |
 | cabalPackage                    | Set the cabal package name, which consists of one or more alphanumeric words separated by hyphens                             |          | {{{cabalPackage}}}                    |
 | cabalVersion                    | Set the cabal version number, consisting of a sequence of one or more integers separated by dots                              | 0.1.0.0  | {{{cabalVersion}}}                    |
+| customTestInstanceModule        | test module used to provide typeclass instances for types not known by the generator                                          |          | {{{customTestInstanceModule}}}        |
 | configType                      | Set the name of the type used for configuration                                                                               |          | {{{configType}}}                      |
 | dateFormat                      | format string used to parse/render a date                                                                                     | %Y-%m-%d | {{{dateFormat}}}                      |
 | dateTimeFormat                  | format string used to parse/render a datetime. (Defaults to [formatISO8601Millis][1] when not provided)                       |          | {{{dateTimeFormat}}}                  |

modules/openapi-generator/src/main/resources/haskell-http-client/haskell-http-client.cabal.mustache

@@ -113,5 +113,6 @@ test-suite tests
   other-modules:
       ApproxEq
       Instances
-      PropMime
+      PropMime{{#customTestInstanceModule}}
+      {{.}}{{/customTestInstanceModule}}
   default-language: Haskell2010

modules/openapi-generator/src/main/resources/haskell-http-client/tests/Instances.mustache

@@ -3,7 +3,8 @@
 module Instances where
 
 import {{baseModule}}.Model
-import {{baseModule}}.Core
+import {{baseModule}}.Core{{#customTestInstanceModule}}
+import {{.}} (){{/customTestInstanceModule}}
 
 import qualified Data.Aeson as A
 import qualified Data.ByteString.Lazy as BL

modules/openapi-generator/src/main/resources/haskell-http-client/tests/Test.mustache

@@ -10,7 +10,8 @@ import Test.Hspec
 import Test.Hspec.QuickCheck
 
 import PropMime
-import Instances ()
+import Instances (){{#customTestInstanceModule}}
+import {{.}} (){{/customTestInstanceModule}}
 
 import {{baseModule}}.Model
 import {{baseModule}}.MimeTypes

samples/client/petstore/haskell-http-client/README.md

@@ -62,6 +62,7 @@ These options allow some customization of the code generation process.
 | baseModule                      | Set the base module namespace                                                                                                 |          | OpenAPIPetstore                      |
 | cabalPackage                    | Set the cabal package name, which consists of one or more alphanumeric words separated by hyphens                             |          | openapi-petstore                    |
 | cabalVersion                    | Set the cabal version number, consisting of a sequence of one or more integers separated by dots                              | 0.1.0.0  | 0.1.0.0                    |
+| customTestInstanceModule        | test module used to provide typeclass instances for types not known by the generator                                          |          |         |
 | configType                      | Set the name of the type used for configuration                                                                               |          | OpenAPIPetstoreConfig                      |
 | dateFormat                      | format string used to parse/render a date                                                                                     | %Y-%m-%d | %Y-%m-%d                      |
 | dateTimeFormat                  | format string used to parse/render a datetime. (Defaults to [formatISO8601Millis][1] when not provided)                       |          |                   |