code: def test_validates_missing_covariates(spark, rg):
      num_samples = 10
      genotype_df = pd.DataFrame(rg.random((num_samples, 3)))
      phenotype_df = pd.DataFrame(rg.random((num_samples, 5)))
      covariate_df = pd.DataFrame(rg.random((num_samples, 2)))
      covariate_df.loc[0, 0] = np.nan
      with pytest.raises(ValueError):
          run_linear_regression_spark(
              spark, genotype_df, phenotype_df, covariate_df
          )
  
imports: import functions
  import numpy
  import statsmodels.api
  import pandas
  import glow.gwas.functions
  import glow.gwas.lin_reg
  import pytest
label_desc: Use image node_id 20 for calling a global function with example usage: test_validates_missing_covariates(spark, rg) without return types