class_docstr: Common tests for all variations of IntervalIndex construction. Input data
  to be supplied in breaks format, then converted by the subclass method
  get_kwargs_from_breaks to the expected format.
code: def test_constructor_dtype(self, constructor, breaks, subtype):
      # GH 19262: conversion via dtype parameter
      expected_kwargs = self.get_kwargs_from_breaks(
          breaks.astype(subtype)
      )
      expected = constructor(**expected_kwargs)
  
      result_kwargs = self.get_kwargs_from_breaks(breaks)
      iv_dtype = IntervalDtype(subtype, "right")
      for dtype in (iv_dtype, str(iv_dtype)):
          result = constructor(dtype=dtype, **result_kwargs)
          tm.assert_index_equal(result, expected)
  
imports: from functools import partial
  import numpy
  import pytest
  import pandas.util._test_decorators
  from pandas.core.dtypes.common import is_unsigned_integer_dtype
  from pandas.core.dtypes.dtypes import IntervalDtype
  from pandas import Categorical, CategoricalDtype, CategoricalIndex, Index, Interval, IntervalIndex, date_range, notna, period_range, timedelta_range
  import pandas._testing
  from pandas.core.arrays import IntervalArray
  import pandas.core.common
label_desc: Use image node_id 2 for calling the ConstructorTests obj's underlying member method code with example usage: obj.test_constructor_dtype(constructor, breaks, subtype) without return types