tests: adds missing cast to ensure the right walker method is being called

Signed-off-by: Vincent Biret <vibiret@microsoft.com>

Author: baywet

test/Microsoft.OpenApi.Tests/Validations/OpenApiHeaderValidationTests.cs

@@ -86,7 +86,7 @@ public void ValidateExamplesShouldNotHaveDataTypeMismatchForSimpleSchema()
             // Act
             var validator = new OpenApiValidator(ValidationRuleSet.GetDefaultRuleSet());
             var walker = new OpenApiWalker(validator);
-            walker.Walk(header);
+            walker.Walk((IOpenApiHeader)header);
 
             warnings = validator.Warnings;
             var result = !warnings.Any();

test/Microsoft.OpenApi.Tests/Validations/OpenApiSchemaValidationTests.cs

@@ -26,7 +26,7 @@ public void ValidateDefaultShouldNotHaveDataTypeMismatchForSimpleSchema()
             // Act
             var validator = new OpenApiValidator(ValidationRuleSet.GetDefaultRuleSet());
             var walker = new OpenApiWalker(validator);
-            walker.Walk(schema);
+            walker.Walk((IOpenApiSchema)schema);
 
             warnings = validator.Warnings;
             var result = !warnings.Any();
@@ -50,7 +50,7 @@ public void ValidateExampleAndDefaultShouldNotHaveDataTypeMismatchForSimpleSchem
             // Act
             var validator = new OpenApiValidator(ValidationRuleSet.GetDefaultRuleSet());
             var walker = new OpenApiWalker(validator);
-            walker.Walk(schema);
+            walker.Walk((IOpenApiSchema)schema);
 
             warnings = validator.Warnings;
             bool result = !warnings.Any();
@@ -92,7 +92,7 @@ public void ValidateEnumShouldNotHaveDataTypeMismatchForSimpleSchema()
             // Act
             var validator = new OpenApiValidator(ValidationRuleSet.GetDefaultRuleSet());
             var walker = new OpenApiWalker(validator);
-            walker.Walk(schema);
+            walker.Walk((IOpenApiSchema)schema);
 
             warnings = validator.Warnings;
             var result = !warnings.Any();