Multiple changes.

- Provide a method to reopen the database environment if closed.
 - Add #keys, which returns an array of keys for the current collection.
 - Finish collection/namespace implementation.
 - Add various aliases (collection->namespace, etc)
 - Add #clear, which destroys data for a the current collection.
   If called in the main db, destroys all.  Don't close the environment
   after a #clear, just the dbi handle.
 - Various bugfixes.

FossilOrigin-Name: 8b00d59e8c5269266f3c6c0d10056a1c0fe1bb583ffbe099a6ed0dac3baf3a66

spec/mdbx/database_spec.rb

@@ -10,7 +10,7 @@ RSpec.describe( MDBX::Database ) do
 			to raise_exception( NoMethodError, /private/ )
 	end
 
-	it "knows the db handle open/close state" do
+	it "knows the env handle open/close state" do
 		db = described_class.open( TEST_DATABASE.to_s )
 		expect( db.closed? ).to be_falsey
 		db.close
@@ -33,29 +33,95 @@ RSpec.describe( MDBX::Database ) do
 			db.close
 		end
 
+		it "can be reopened" do
+			db.close
+			expect( db ).to be_closed
+			db.reopen
+			expect( db ).to_not be_closed
+		end
+
 		it "knows its own path" do
-			expect( db.path ).to match( %r|data/testdb$| )
+			expect( db.path ).to match( %r|tmp/testdb$| )
 		end
 
 		it "fails if opened again within the same process" do
 			# This is a function of libmdbx internals, just testing
-			# here for behaviorals.
+			# here for behavior.
 			expect {
 				described_class.open( TEST_DATABASE.to_s )
 			}.
 			to raise_exception( MDBX::DatabaseError, /environment is already used/ )
 		end
 
+		it "can remove a key by setting its value to nil" do
+			db[ 'test' ] = "hi"
+			expect( db['test'] ).to eq( 'hi' )
+
+			db[ 'test' ] = nil
+			expect( db['test'] ).to be_nil
+
+			expect { db[ 'test' ] = nil }.to_not raise_exception
+		end
+
+		it "can return an array of its keys" do
+			db[ 'key1' ] = true
+			db[ 'key2' ] = true
+			db[ 'key3' ] = true
+			expect( db.keys ).to include( 'key1', 'key2', 'key3' )
+		end
+	end
+
+
+	context 'collections' do
+
+		let!( :db ) { described_class.open( TEST_DATABASE.to_s, max_collections: 5 ) }
+
+		after( :each ) do
+			db.close
+		end
+
+		it "fail if the max_collections option is not specified when opening" do
+			db.close
+			db = described_class.open( TEST_DATABASE.to_s )
+			db.collection( 'bucket' )
+
+			expect{ db['key'] = true }.to raise_exception( /MDBX_DBS_FULL/ )
+		end
+
+		it "disallows regular key/val storage for namespace keys" do
+			db.collection( 'bucket' )
+			db[ 'okay' ] = 1
+			db.collection( nil )
+
+			expect{ db['bucket'] = 1  }.to raise_exception( /MDBX_INCOMPATIBLE/ )
+		end
+
 		it "defaults to the top-level namespace" do
 			expect( db.collection ).to be_nil
 		end
 
 		it "can set a collection namespace" do
+			expect( db.collection ).to be_nil
+			db[ 'key' ] = true
+
 			db.collection( 'bucket' )
 			expect( db.collection ).to eq( 'bucket' )
-			# TODO: set/retrieve data
+			db[ 'key' ] = false
+
+			db.main
+			expect( db.collection ).to be_nil
+			expect( db['key'] ).to be_truthy
 		end
 
+		it "can be cleared of contents" do
+			db.collection( 'bucket' )
+			10.times {|i| db[i] = true }
+			expect( db[2] ).to be_truthy
+
+			db.clear
+			db.main
+			expect( db['bucket'] ).to be_nil
+		end
 	end
 end