test: add missing tests

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---

Author: headlessNode

lib/node_modules/@stdlib/blas/ext/find-index/test/test.assign.js

@@ -319,6 +319,150 @@ tape( 'the function throws an error if provided a second argument which is not a
 	}
 });
 
+tape( 'the function throws an error if provided a callback which is not a function', function test( t ) {
+	var values;
+	var i;
+	var x;
+	var y;
+
+	x = zeros( [], {
+		'dtype': 'generic'
+	});
+	x = zeros( [], {
+		'dtype': 'int32'
+	});
+
+	values = [
+		'5',
+		5,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		[],
+		{}
+	];
+	for ( i = 0; i < values.length; i++ ) {
+		t.throws( badValue( values[ i ] ), TypeError, 'throws an error when provided ' + values[ i ] );
+	}
+	t.end();
+
+	function badValue( value ) {
+		return function badValue() {
+			findIndex( x, y, value );
+		};
+	}
+});
+
+tape( 'the function throws an error if provided a callback which is not a function (thisArg)', function test( t ) {
+	var values;
+	var i;
+	var x;
+	var y;
+
+	x = zeros( [], {
+		'dtype': 'generic'
+	});
+	x = zeros( [], {
+		'dtype': 'int32'
+	});
+
+	values = [
+		'5',
+		5,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		[],
+		{}
+	];
+	for ( i = 0; i < values.length; i++ ) {
+		t.throws( badValue( values[ i ] ), TypeError, 'throws an error when provided ' + values[ i ] );
+	}
+	t.end();
+
+	function badValue( value ) {
+		return function badValue() {
+			findIndex( x, y, value, {} );
+		};
+	}
+});
+
+tape( 'the function throws an error if provided a callback which is not a function (options)', function test( t ) {
+	var values;
+	var i;
+	var x;
+	var y;
+
+	x = zeros( [], {
+		'dtype': 'generic'
+	});
+	y = zeros( [], {
+		'dtype': 'int32'
+	});
+
+	values = [
+		'5',
+		5,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		[],
+		{}
+	];
+	for ( i = 0; i < values.length; i++ ) {
+		t.throws( badValue( values[ i ] ), TypeError, 'throws an error when provided ' + values[ i ] );
+	}
+	t.end();
+
+	function badValue( value ) {
+		return function badValue() {
+			findIndex( x, y, value, {}, clbk );
+		};
+	}
+});
+
+tape( 'the function throws an error if provided a callback which is not a function (options, thisArg)', function test( t ) {
+	var values;
+	var i;
+	var x;
+	var y;
+
+	x = zeros( [], {
+		'dtype': 'generic'
+	});
+	x = zeros( [], {
+		'dtype': 'int32'
+	});
+
+	values = [
+		'5',
+		5,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		[],
+		{}
+	];
+	for ( i = 0; i < values.length; i++ ) {
+		t.throws( badValue( values[ i ] ), TypeError, 'throws an error when provided ' + values[ i ] );
+	}
+	t.end();
+
+	function badValue( value ) {
+		return function badValue() {
+			findIndex( x, y, {}, value, {} );
+		};
+	}
+});
+
 tape( 'the function throws an error if provided insufficient number of arguments', function test( t ) {
 	var x;
 	var y;