Added tests that can be implemented for any provider to ensure consistency

src/Configuration/Config.AzureKeyVault/test/ConfigurationProviderAzureKeyVaultTest.cs

@@ -0,0 +1,73 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Azure.KeyVault;
+using Microsoft.Azure.KeyVault.Models;
+using Microsoft.Extensions.Configuration.Test;
+using Microsoft.Rest.Azure;
+using Moq;
+
+namespace Microsoft.Extensions.Configuration.AzureKeyVault.Test
+{
+    public class ConfigurationProviderKeyVaultTest : ConfigurationProviderTestBase
+    {
+        protected override (IConfigurationProvider Provider, System.Action Initializer) LoadThroughProvider(
+            TestSection testConfig)
+        {
+            var values = new List<KeyValuePair<string, string>>();
+            SectionToValues(testConfig, "", values);
+
+            return (FromKeyVault(values), () => {});
+        }
+
+        private IConfigurationProvider FromKeyVault(IEnumerable<KeyValuePair<string, string>> data)
+        {
+            const string vaultUri = "https://vault";
+
+            var client = new Mock<IKeyVaultClient>(MockBehavior.Strict);
+            var rawData = data.ToList();
+            var nextPageLink = vaultUri;
+
+            for (var i = 0; i < rawData.Count; i++)
+            {
+                var currentPageLink = nextPageLink;
+                nextPageLink = i < (rawData.Count - 1) ? $"next{i}" : null;
+
+                var secretId = new SecretIdentifier(vaultUri, rawData[i].Key).Identifier;
+
+                var pageMock = new PageMock
+                {
+                    NextPageLink = nextPageLink,
+                    Value = new[] { new SecretItem { Id = secretId, Attributes = new SecretAttributes { Enabled = true } } }
+                };
+
+                if (i == 0)
+                {
+                    client.Setup(c => c.GetSecretsAsync(currentPageLink)).ReturnsAsync(pageMock);
+                }
+                else
+                {
+                    client.Setup(c => c.GetSecretsNextAsync(currentPageLink)).ReturnsAsync(pageMock);
+                }
+
+                client.Setup(c => c.GetSecretAsync(secretId)).ReturnsAsync(new SecretBundle() { Value = rawData[i].Value, Id = secretId });
+            }
+
+            return new AzureKeyVaultConfigurationProvider(
+                    client.Object,
+                    vaultUri,
+                    new DefaultKeyVaultSecretManager());
+        }
+
+        private class PageMock : IPage<SecretItem>
+        {
+            public IEnumerable<SecretItem> Value { get; set; }
+            public IEnumerator<SecretItem> GetEnumerator() => Value.GetEnumerator();
+            IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+            public string NextPageLink { get; set; }
+        }
+    }
+}

src/Configuration/Config.AzureKeyVault/test/Microsoft.Extensions.Configuration.AzureKeyVault.Tests.csproj

@@ -4,6 +4,10 @@
     <TargetFramework>net461</TargetFramework>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\Config\test\Microsoft.Extensions.Configuration.Tests.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="Microsoft.Extensions.Configuration.AzureKeyVault" />
     <Reference Include="Microsoft.Extensions.Configuration.Test.Common" />

src/Configuration/Config.CommandLine/test/ConfigurationProviderCommandLineTest.cs

@@ -0,0 +1,50 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Extensions.Configuration.Test;
+using Xunit;
+
+namespace Microsoft.Extensions.Configuration.CommandLine.Test
+{
+    public class ConfigurationProviderCommandLineTest : ConfigurationProviderTestBase
+    {
+        protected override (IConfigurationProvider Provider, Action Initializer) LoadThroughProvider(
+            TestSection testConfig)
+        {
+            var args = new List<string>();
+            SectionToArgs(args, "", testConfig);
+
+            var provider = new CommandLineConfigurationProvider(args);
+
+            return (provider, () => { });
+        }
+
+        private void SectionToArgs(List<string> args, string sectionName, TestSection section)
+        {
+            foreach (var tuple in section.Values.SelectMany(e => e.Value.Expand(e.Key)))
+            {
+                args.Add($"--{sectionName}{tuple.Key}={tuple.Value}");
+            }
+
+            foreach (var tuple in section.Sections)
+            {
+                SectionToArgs(args, sectionName + tuple.Key + ":", tuple.Section);
+            }
+        }
+
+        [Fact]
+        public override void Load_from_single_provider_with_duplicates_throws()
+        {
+            AssertConfig(BuildConfigRoot(LoadThroughProvider(TestSection.DuplicatesTestConfig)));
+        }
+
+        [Fact]
+        public override void Load_from_single_provider_with_differing_case_duplicates_throws()
+        {
+            AssertConfig(BuildConfigRoot(LoadThroughProvider(TestSection.DuplicatesDifferentCaseTestConfig)));
+        }
+    }
+}

src/Configuration/Config.CommandLine/test/Microsoft.Extensions.Configuration.CommandLine.Tests.csproj

@@ -4,6 +4,10 @@
     <TargetFrameworks>$(StandardTestTfms)</TargetFrameworks>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\Config\test\Microsoft.Extensions.Configuration.Tests.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="Microsoft.Extensions.Configuration.CommandLine" />
     <Reference Include="Microsoft.Extensions.Configuration.Test.Common" />

src/Configuration/Config.EnvironmentVariables/test/ConfigurationProviderEnvironmentVariablesTest.cs

@@ -0,0 +1,30 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Extensions.Configuration.Test;
+
+namespace Microsoft.Extensions.Configuration.EnvironmentVariables.Test
+{
+    public class ConfigurationProviderEnvironmentVariablesTest : ConfigurationProviderTestBase
+    {
+        protected override (IConfigurationProvider Provider, Action Initializer) LoadThroughProvider(
+            TestSection testConfig)
+        {
+            var values = new List<KeyValuePair<string, string>>();
+            SectionToValues(testConfig, "", values);
+
+            var provider = new EnvironmentVariablesConfigurationProvider(null);
+
+            return (provider, () => provider.Load(new Hashtable(values.ToDictionary(e => e.Key, e => e.Value))));
+        }
+
+        public override void Load_from_single_provider_with_differing_case_duplicates_throws()
+        {
+            AssertConfig(BuildConfigRoot(LoadThroughProvider(TestSection.DuplicatesDifferentCaseTestConfig)));
+        }
+    }
+}

src/Configuration/Config.EnvironmentVariables/test/EnvironmentVariablesTest.cs

@@ -1,7 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using System.Collections;
 using Microsoft.Extensions.Configuration.Test;
 using Xunit;

src/Configuration/Config.EnvironmentVariables/test/Microsoft.Extensions.Configuration.EnvironmentVariables.Tests.csproj

@@ -4,6 +4,10 @@
     <TargetFrameworks>$(StandardTestTfms)</TargetFrameworks>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\Config\test\Microsoft.Extensions.Configuration.Tests.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" />
     <Reference Include="Microsoft.Extensions.Configuration.Test.Common" />

src/Configuration/Config.Ini/test/ConfigurationProviderIniTest.cs

@@ -0,0 +1,43 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Linq;
+using System.Text;
+using Microsoft.Extensions.Configuration.Test;
+
+namespace Microsoft.Extensions.Configuration.Ini.Test
+{
+    public class ConfigurationProviderIniTest : ConfigurationProviderTestBase
+    {
+        protected override (IConfigurationProvider Provider, Action Initializer) LoadThroughProvider(
+            TestSection testConfig)
+        {
+            var iniBuilder = new StringBuilder();
+            SectionToIni(iniBuilder, "", testConfig);
+
+            var provider = new IniConfigurationProvider(
+                new IniConfigurationSource
+                {
+                    Optional = true
+                });
+
+            var ini = iniBuilder.ToString();
+            return (provider, () => provider.Load(TestStreamHelpers.StringToStream(ini)));
+        }
+
+        private void SectionToIni(StringBuilder iniBuilder, string sectionName, TestSection section)
+        {
+            foreach (var tuple in section.Values.SelectMany(e => e.Value.Expand(e.Key)))
+            {
+                iniBuilder.AppendLine($"{tuple.Key}={tuple.Value}");
+            }
+
+            foreach (var tuple in section.Sections)
+            {
+                iniBuilder.AppendLine($"[{sectionName}{tuple.Key}]");
+                SectionToIni(iniBuilder, tuple.Key + ":", tuple.Section);
+            }
+        }
+    }
+}

src/Configuration/Config.Ini/test/Microsoft.Extensions.Configuration.Ini.Tests.csproj

@@ -4,6 +4,10 @@
     <TargetFrameworks>$(StandardTestTfms)</TargetFrameworks>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\Config\test\Microsoft.Extensions.Configuration.Tests.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="Microsoft.Extensions.Configuration.Ini" />
     <Reference Include="Microsoft.Extensions.Configuration.Test.Common" />

src/Configuration/Config.Json/test/ConfigurationProviderJsonTest.cs

@@ -0,0 +1,56 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Linq;
+using System.Text;
+using Microsoft.Extensions.Configuration.Json;
+using Microsoft.Extensions.Configuration.Test;
+
+namespace Microsoft.Extensions.Configuration
+{
+    public class ConfigurationProviderJsonTest : ConfigurationProviderTestBase
+    {
+        public override void Load_from_single_provider_with_duplicates_throws()
+        {
+            // JSON provider doesn't throw for duplicate values with the same case
+            AssertConfig(BuildConfigRoot(LoadThroughProvider(TestSection.DuplicatesTestConfig)));
+        }
+
+        protected override (IConfigurationProvider Provider, Action Initializer) LoadThroughProvider(TestSection testConfig)
+        {
+            var jsonBuilder = new StringBuilder();
+            SectionToJson(jsonBuilder, testConfig);
+
+            var provider = new JsonConfigurationProvider(
+                new JsonConfigurationSource
+                {
+                    Optional = true
+                });
+
+            var json = jsonBuilder.ToString();
+
+            return (provider, () => provider.Load(TestStreamHelpers.StringToStream(json)));
+        }
+
+        private void SectionToJson(StringBuilder jsonBuilder, TestSection section)
+        {
+            jsonBuilder.AppendLine("{");
+
+            foreach (var tuple in section.Values)
+            {
+                jsonBuilder.AppendLine(tuple.Value.AsArray != null
+                    ? $"'{tuple.Key}': [{string.Join(", ", tuple.Value.AsArray.Select(v => $"'{v}'"))}],"
+                    : $"'{tuple.Key}': '{tuple.Value.AsString}',");
+            }
+
+            foreach (var tuple in section.Sections)
+            {
+                jsonBuilder.Append($"'{tuple.Key}': ");
+                SectionToJson(jsonBuilder, tuple.Section);
+            }
+
+            jsonBuilder.AppendLine("},");
+        }
+    }
+}

src/Configuration/Config.Json/test/JsonConfigurationTest.cs

@@ -168,4 +168,4 @@ public void ThrowFormatExceptionWhenFileIsEmpty()
             var exception = Assert.Throws<FormatException>(() => LoadProvider(@""));
         }
     }
-}
+}

src/Configuration/Config.Json/test/Microsoft.Extensions.Configuration.Json.Tests.csproj

@@ -4,6 +4,10 @@
     <TargetFrameworks>$(StandardTestTfms)</TargetFrameworks>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\Config\test\Microsoft.Extensions.Configuration.Tests.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="Microsoft.Extensions.Configuration.Json" />
     <Reference Include="Microsoft.Extensions.Configuration.Test.Common" />

src/Configuration/Config.KeyPerFile/test/ConfigurationProviderCommandLineTest.cs

@@ -0,0 +1,43 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Extensions.Configuration.Test;
+using Microsoft.Extensions.FileProviders;
+
+namespace Microsoft.Extensions.Configuration.KeyPerFile.Test
+{
+    public class ConfigurationProviderCommandLineTest : ConfigurationProviderTestBase
+    {
+        protected override (IConfigurationProvider Provider, Action Initializer) LoadThroughProvider(
+            TestSection testConfig)
+        {
+            var testFiles = new List<IFileInfo>();
+            SectionToTestFiles(testFiles, "", testConfig);
+
+            var provider = new KeyPerFileConfigurationProvider(
+                new KeyPerFileConfigurationSource
+                {
+                    Optional = true,
+                    FileProvider = new TestFileProvider(testFiles.ToArray())
+                });
+
+            return (provider, () => { });
+        }
+
+        private void SectionToTestFiles(List<IFileInfo> testFiles, string sectionName, TestSection section)
+        {
+            foreach (var tuple in section.Values.SelectMany(e => e.Value.Expand(e.Key)))
+            {
+                testFiles.Add(new TestFile(sectionName + tuple.Key, tuple.Value));
+            }
+
+            foreach (var tuple in section.Sections)
+            {
+                SectionToTestFiles(testFiles, sectionName + tuple.Key + "__", tuple.Section);
+            }
+        }
+    }
+}

src/Configuration/Config.KeyPerFile/test/KeyPerFileTests.cs

@@ -1,8 +1,10 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
 using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using System.Text;
 using Microsoft.Extensions.FileProviders;
 using Microsoft.Extensions.Primitives;

src/Configuration/Config.KeyPerFile/test/Microsoft.Extensions.Configuration.KeyPerFile.Tests.csproj

@@ -4,6 +4,10 @@
     <TargetFrameworks>$(StandardTestTfms)</TargetFrameworks>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\Config\test\Microsoft.Extensions.Configuration.Tests.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="Microsoft.Extensions.Configuration.KeyPerFile" />
   </ItemGroup>