* <p>The collection fails to resolve if it contains providers which are not present.
     */
    FileCollectionInternal resolving(String displayName, Object sources);

    /**
     * Creates a {@link FileCollection} with the given files as content.
     *
     * <p>The collection is live and resolves the files on each query.
     *
     * <p>The collection ignores providers which are not present.
     */

 */

package org.gradle.util

import org.gradle.api.internal.provider.DefaultProviderFactory
import org.gradle.api.internal.provider.Providers
import org.gradle.api.provider.Provider

public class TestProviderFactory extends DefaultProviderFactory {

    @Override
    Provider<String> environmentVariable(String variableName) {
        return Providers.ofNullable(System.getenv(variableName))
    }

    @Override

    def "can add the same provider twice"() {
        def provider = provider("foo")

        when:
        source.addPending(provider)
        source.addPending(provider)

        then:
        source.size() == 1
        source.contains("foo")
    }

    def "an element added as both a provider and a realized value is not duplicated"() {
        when:

        }
        return new String(output.toByteArray(), Charset.defaultCharset())
    }
}
// end::value-source[]

// tag::create-provider[]
def gitVersionProvider = providers.of(GitVersionValueSource.class) {}
def gitVersion = gitVersionProvider.get()

        }
        return String(output.toByteArray(), Charset.defaultCharset())
    }
}
// end::value-source[]

// tag::create-provider[]
val gitVersionProvider = providers.of(GitVersionValueSource::class) {}
val gitVersion = gitVersionProvider.get()

	Resources []string `json:"resources"`
	// providers is a list of transformers to be used for reading and writing the resources to disk.
	// eg: aesgcm, aescbc, secretbox, identity, kms.
	Providers []ProviderConfiguration `json:"providers"`
}

// ProviderConfiguration stores the provided configuration for an encryption provider.
type ProviderConfiguration struct {

                content.convention(providers.systemProperty("\${project.name}Content").orElse(project.name))
                timestamp.convention(providers.systemProperty("\${project.name}Timestamp").map { Long.parseLong(it) }.orElse(123L))

        where:
        description                | propertyValue
        "Java type"                | "throw new RuntimeException(\"BOOM\")"
        "Provider"                 | "return providers.provider { throw new RuntimeException(\"BOOM\") }"
        "Provider in a collection" | "return [providers.provider { throw new RuntimeException(\"BOOM\") }]"

    }

    def "null on nested bean is validated #description"() {

        def buildScript = """
            tasks.register('executionCredentials') {
                def providers = project.providers
                doLast {
                    providers.credentials($credentialsType, 'test').get()
                }
            }
        """
        file('submodule1/build.gradle') << buildScript

        def configurationCache = newConfigurationCacheFixture()
        buildFile '''
            def userProvider = providers.gradleProperty("ci").map { "" }.orElse(providers.systemProperty("user"))
            def versionMajorProvider = providers.gradleProperty("versionMajor").orElse("1")
            def versionMinorProvider = providers.gradleProperty("versionMinor").orElse("2")
            def versionNameProvider = versionMajorProvider