{Context,Chained}Error: New modules

This will allow us to provide additional useful information for structure
logging.

2 files changed, 135 insertions, 0 deletions

diff --git a/test/error/ChainedErrorTest.ts b/test/error/ChainedErrorTest.ts
new file mode 100644
index 0000000..d6d98ed
--- /dev/null
+++ b/test/error/ChainedErrorTest.ts
@@ -0,0 +1,67 @@
+/**
+ * Tests error chaining
+ *
+ *  Copyright (C) 2010-2019 R-T Specialty, LLC.
+ *
+ *  This file is part of the Liza Data Collection Framework.
+ *
+ *  liza is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import * as sut from "../../src/error/ChainedError";
+import { expect } from 'chai';
+
+
+describe( 'ChainedError', () =>
+{
+    it( "can be created with generic error", () =>
+    {
+        const eprev = new Error( "previous error" );
+
+        expect( sut.chain( new Error( "new error" ), eprev ).chain )
+            .to.equal( eprev );
+    } );
+
+
+    it( "can be chained to arbitrary depth", () =>
+    {
+        const e1 = new Error( "lower" );
+        const e2 = sut.chain( new Error( "mid" ), e1 );
+        const e3 = sut.chain( new Error( "outer" ), e2 );
+
+        expect( sut.isChained( e3 ) ).to.be.true;
+        expect( sut.isChained( e2 ) ).to.be.true;
+        expect( sut.isChained( e1 ) ).to.be.false;
+    } );
+
+
+    it( "provides type predicate for TypeScript", () =>
+    {
+        const inner = new Error( "inner" );
+
+        // force to Error to discard ChainedError type
+        const outer: Error = sut.chain( new Error( "outer" ), inner );
+
+        if ( sut.isChained( outer ) )
+        {
+            // if isChained was properly defined, then outer should now
+            // have type ChainedError, and so this should compile
+            expect( outer.chain ).to.equal( inner );
+        }
+        else
+        {
+            expect.fail();
+        }
+    } );
+} );
diff --git a/test/error/ContextErrorTest.ts b/test/error/ContextErrorTest.ts
new file mode 100644
index 0000000..c02c3f2
--- /dev/null
+++ b/test/error/ContextErrorTest.ts
@@ -0,0 +1,68 @@
+/**
+ * Tests error context
+ *
+ *  Copyright (C) 2010-2019 R-T Specialty, LLC.
+ *
+ *  This file is part of the Liza Data Collection Framework.
+ *
+ *  liza is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import * as sut from "../../src/error/ContextError";
+import { expect } from 'chai';
+
+
+describe( 'ContextError', () =>
+{
+    it( "can be created with generic error", () =>
+    {
+        const context = { foo: "context" };
+
+        expect( sut.context( new Error( "test error" ), context ).context )
+            .to.equal( context );
+    } );
+
+
+    it( "provides type predicate for TypeScript", () =>
+    {
+        const context = { bar: "baz context" };
+
+        // force to Error to discard ContextError type
+        const e: Error = sut.context( new Error( "test error" ), context );
+
+        if ( sut.hasContext( e ) )
+        {
+            // if isChained was properly defined, then outer should now
+            // have type ChainedError, and so this should compile
+            expect( e.context ).to.equal( context );
+        }
+        else
+        {
+            expect.fail();
+        }
+    } );
+
+
+    it( "can create typed contexts", () =>
+    {
+        type FooErrorContext = { foo: string };
+
+        // this is the actual test
+        const e: sut.ContextError<FooErrorContext> =
+            sut.context( new Error( "test error" ), { foo: "context" } );
+
+        // contravariance check (would fail to compile)
+        expect( sut.hasContext( e ) ).to.be.true;
+    } );
+} );